Starting a Garden from Scratch

This year, like last year, we started a new garden where there had previously been grass. We have therefore had opportunities to try out various strategies. Here’s the outcome of these experiments.

Garden bed preparation

Last year, we tried turning over the sod so that the grass would die and the roots would be exposed and dry up. This doesn’t work: grass is feisty, and just grows up around the edges of the sod, even if the part beneath dies. The implications for fertility and soil life also seem mediocre with this process.

Both times, we tried removing the grass and shaking the earth off the roots. This also leaves a lot of roots and also weed seeds which have been lying dormant, and therefore it takes no time at all for a little jungle to spring up from the earth.

We tried sheet mulching, and this is probably the most successful method. The trouble is it takes a lot of compost and mulch to cover a large area, so this year we: a) removed the grass and superficial topsoil and composted it, b) removed the rest of the topsoil, c) loosened the subsoil, d) laid down the cardboard and replaced the topsoil on top of it, followed by dry mulch (bracken or hemp). This was a long and difficult process which we could have avoided if we had had masses of compost and just done the sheet mulching straight on top of the grass. The ground was very compacted (it had been a horse pasture), which was another reason we wanted to loosen the soil before sheet mulching.

The results were very good; we found that the soil stayed moist for a long time under the cardboard, and we had little trouble with weeds. I think the cardboard took care of any remaining grass roots, while the mulch on top took care of the seeds left in the soil. Sheet mulching was perfect for the nightshades and perennial cabbages. In the future, I think we'll try making it thicker, with more carbon mulch, mixed if necessary with blood meal or some other high nitrogen material, for additional on-site compost production and increased benefits from the sheet-mulching.

For beds in which we wanted to plant seeds (greens, beets, carrots, flowers), we decided not to sheet mulch as this didn’t seem compatible with starting seeds. The greens we planted early did alright because they grew fast and out-competed weeds anyway. Our kale and beet patch was very weedy, though the weeds were mostly very small. Presumably over the years there will be less weeds as the seeds that were present in the ground run out.

Start Small

We didn’t! We really wanted a big garden, something that would be challenging and full of food and lessons. The thing is, the bigger it is, the more dispersed your energy gets and the less effort you can spend on it per surface area. Therefore a larger garden will be less productive per unit of surface area. We definitely observed this as there were always, at any given time, parts that weren’t producing. This is the basic principle of square foot gardening. While in Montreal, I saw square foot gardening as a sort of punishment or affliction that city dwellers have to put up with due to space restrictions. Now I appreciate the underlying tenets: the smaller the garden, the easier it will be to take care of it, and the more productive it will be per unit of area.

The other thing is that we burned out a little after the mad rush to plant of the spring, and pulled back after that from the garden. I think that if we had started fewer plants of fewer varieties, we would have been less overwhelmed and more contented with our garden during the summer. We felt the pressure also to plant any successful seedlings as it was very hard to discard any, but in the end our garden was a bit too dense and unwieldy. So, when starting our own seedlings, we need to remember that some of them will need to be sacrificed for the others to grow optimally.

Also, a new garden usually takes a lot of raw materials: compost, mulch, sticks for trellises, maybe some garden furniture, stones or other landscaping stuff. Therefore starting small and really enhancing the fertility and beauty of the garden seems like a better course of action than spreading mulch too thin to be effective or running out of compost/manure half way through. After the first year, hopefully mulch plants will kick into action and the compost pile will be yielding, which will provide the resources for a successful expansion.

Plant Selection

I think that starting with lots of perennials and a few annuals would be a good balance. Perennials need time to get established, so I’d recommend putting them in first, so that in the second year there will already be a bunch of stuff growing and you can concentrate your energy on expanding on that. If you plant just annuals the first year, you will have to start all over again the next time. Annuals are not the best use of energy (or money), in the longer run.

On the other hand, it's good to make sure that some really reliable producers are included: I'm thinking about chard, beats, kale, herbs. Stuff that most likely you'll get more of than you want, unless you try very hard to mess things up. And also, I wish we'd used more earlier producers. We had very little before mid-July and the first tomatoes. Early producers like turnips, beats, greens, spinach, kohlrabi, while not the most exciting to eat (I think), are really nice to have around for their fast growth. They really help to extend the season both ways.

Planting patterns

We were a bit obsessed with companion planting this year. It must be said that in winter, when the garden is just a dream and we long to be outside with the sun warming our bones, thinking about plant combinations is like fantasizing! In the end though, companion planting is a nebulous pseudoscience which should be taken with a pinch of salt. It’s very hard to know what combinations are going to work (marginally) better than others, which you learn by observation rather than book/internet research anyway. So, no point sweating over that too much!

Rows

We’ve been resisting planting in rows, which we saw as an unnatural imposition of puritanical will upon the naturally flowing patterns of the plant world. The fact is, I think that some things benefit from being planted in rows, especially root vegetables (our broadcasted carrot seeds didn't come to any good, and we were mostly powerless to effectively care for them, spread all over the place as they were) and some alliums that need to be fairly weed free and thinned correctly. It’s virtually impossible to effectively weed young plants that aren’t in rows! Rows make is easier to identify young seedlings, and to thin them when the time comes, and then also to harvest them. Ease of harvesting was something we totally didn’t consider at the end of a rugged winter, when it was unimaginable that harvesting, that holy sacred grail, could ever be anything but pure bliss! It's really something that needs to be planned for in order to make the best use of the garden's gifts!

On the other hand, bigger plants that grow for the whole season, like tomatoes or peppers, don’t seem to need to be planted in lines as much (except maybe for ease of trellising, and, again, harvesting). Plant guilds, which are something we are just beginning to explore, also brings an end to the need for rows, but this is sort of beyond the scope of a veggie garden.

Conclusion

My biggest take home messages from this year are: we must make sure to manage our energy for our own pleasure and for the benefit of the garden (start small, don't waste energy on marginally beneficial plants, use perennials rather than annuals when possible), and relax about the theory: stuff like companion planting, soil fertility, etc., which you learn as you go along anyway, rather than sweating over volumes of gardening books that usually don't agree anyway. A creative balance of experimentation and sure shots will ensure learning and satisfaction will both flow from the garden.

Three Sisters Musings

So now I’m sitting in the back of the motor home, and we’ve just passed Ottawa. This is a good time to spend reading and writing blog posts! Reading through Toby Hemenway’s “Gaia’s Garden: A Guide to Home-Scale Permaculture” (what an awesome book!), I came across a discussion of the Three Sisters. Since returning to Turtle Island (aka North America), I’ve also had conversations about this guild with other gardeners. One of our friends even has a tattoo of the Three Sisters on his calf! So here are some more thoughts that came out of all this. It seems to me that the main benefit of this guild over separate patches is to the corn, which, according to one Jane Mt. Pleasant of Cornell University, yields about 20% more (measured in calories) than corn grown alone. Plus you get some squash and some beans in the deal, but I think that if you want a serious amount of beans, you need a separate bean patch (which is easy enough to do).

I’ve been puzzled by the mound pattern of planting for the corn and beans that I have seen in several instructions. They describe mounds about 20 inches across and 12 inches high, or some variation of these dimensions. I never quite understood the point, except maybe so that the ground would heat up sooner in the spring. The method described in Gaia’s Garden seems to make more sense in this respect: corn is planted 3 or 4 kernels per hole, about 3 feet apart. No thinning is done as you want 2 or 3 stalks per hole, which explains the planting distance. It’s only when the corn sprouts that you mound it, which helps warm the ground and speed up the growth of the corn. Beyond this, bean and squash planting occurs in the same way, about two weeks after the corn has sprouted. The author recommends inoculating the beans to ensure the presence of nitrogen-fixing bacteria.

Another thing that could really help boost squash and bean production is adding some pollinator attractors, just like the Anasazi of the Southwest added the Rocky Mountain bee plant (Cleome serulata), thereby bringing in the experience and blessings of the insect nation. We noticed that our squashes were aborting from lack of pollination, and to be fair with the bees, who are undoubtedly doing their best as it is, the squash flowers were fairly few and far between at any given moment, and they were hidden beneath a dense canopy of leaves. In addition, pollination would require pollinators to visit a male flower first, and then a female flower, of the same squash species! So, some early blooming flowers would be a small compensation for the efforts of insect visitors.

In the future I’d try the method described in Gaia’s Garden. I think a lot of people get discouraged after trying the Three Sisters once, especially if they are used to another method that worked pretty well for them, but considering the variations in the planting instructions it is only to be expected that results will vary.

Garden conclusion 2010

Our garden adventure has drawn to an end this year, somewhat prematurely as we left France to return across the pond, to continue our North American adventures. I will leave here some impressions and lessons we learnt from this experience, may it help or at least amuse any gardeners reading this!

• The Three Sisters are a lot of fun to play with! (See multiple other posts in this topic)

• Perennial cabbages are amazing!

• 10 varieties of cherry tomatoes makes your plate pretty and your mouth water!

• Chickens are amazing garden companions, I wouldn’t like to be without them!

• Sheet mulching is great; top mulching is key!

• Many things can be started as seedlings, for the better: beets, legumes, cabbages, squash…

• Many weeds are delicious! Few are a serious pain!

Overall when I think of the lessons learned in the garden this year, I think of a lot of things I want to do differently next time:

• Plant lots of early ripening vegetables, even if they are not the usual favourites: beets, turnips, radishes, kohlrabi are great for an early harvest, are really are much better when they come from your very own garden. I don’t want to be waiting for my first tomatoes in mid-July for a first harvest again!

• Greens need to be planted regularly. I know it, but I forget it. We only got greens for a short period this year because we made only one planting.

• More perennials! I want perennial alliums, cabbages, groundcherries (for real! Physalis heterophylla), sunflowers, lovage, watercress, Good King Henry, New Zealand Spinach, etc.

• More guilds! Using nitrogen fixing trees in the garden, creating perennial guilds with walnuts, goumis, paw-paws, wolfberries, currants, maypop, hazelnuts, mulberries, Saskatoon berries, etc.

• Back to more conventional plants though, I want to grow at least a few totally reliable veggies, like chard and cabbage. Things that can be counted on. I’ll be more selective and ignore the dodgy-sounding plants like garden huckleberry or snake gourds. I mean, experimenting is good, but selecting experiments that seem promising beats being indiscriminate and buying anything I don’t know for the sake of novelty!

• There’s no rush to plant early. Plants that are seeded or transplanted into a cold ground will not do well, whereas plants that might be started later will easily catch up. Plant growth isn’t linear in that way, it depends on the weather conditions. Maybe with a good greenhouse or coldframe set up it can still be beneficial to plant early, but otherwise it can be a waste of time.

Looking forward to more gardening, farming, permaculturing wildly in the future!

Garden Huckleberry

One of our garden experiments this year (well, everything was an experiment, really!) was the "garden huckleberry", a nightshade-family fruit totally unrelated to true huckleberries. It is supposedly a cultivar of black nightshade, which would make it Solanum nigrum var. melanocerasum. I have not been able to find a whole lot of information about it, but apparently it is from West Africa.

Garden huckleberry grows into a small annual bush, roughly the size and aspect of a tomatillo plant (though it doesn't flop over pathetically like tomatillos do, bless their leafy hearts). The little white flowers give way to a multitude of green berries that turn black and shiny. We had no problem growing these plants, they had no diseases or pests, and didn't mind irregular watering. They seem to prefer it hot. We got about 2L of berries in our first harvest from 6 plants, which is not bad, I think.

Now, the tricky question is what do they taste like? Well, firstly, you don't eat them raw. They are simply no good. Rather tasteless, slightly metallic, and not worth your time of day. You need to cook them, and not any old way either. First, you need to parboil them for 10 minutes with some baking soda. During this stage, it produces a most amazing green foam (photo). Then you rinse the berries, and cook them with lemon juice, during which process the mixture turns deep purple, and you add sugar at the end. At last, you are supposed to obtain berries that taste like blueberries. Well, my assessment is that they taste like damn bitter blueberries. Rosemary is rather less elogious, and says they taste like bitter sweetened boiled grass.

So basically, this plant is not really worth the time or garden space, and we won't grow it again. I find than regular black nightshade has much nicer tasting berries (and no, black nightshade is not toxic when ripe). A google search quickly demonstrates the overwhelming proportion of people who feel the same way about garden huckleberry, and only a small number of gardeners seem to want to grow it for more than one season!

Honestly though, it would make a nice ornamental plant, but I don't think I'll try eating it again...

Sprouting mixes are fun to plant, but...

We have tried using seeds from sprouting mixes from the health food store, which has been fun, but has produced some unexpected crops.

For a start, we broadcasted some seeds labelled "cresson" (cress). We expected this to mean water cress, which is generally what is meant in France by cresson (cresson de fontaine). Well, it turned out to be peppergrass (cresson alénois). So now we have a big bed of peppergrass!


We also planted mustard from a bag of sprouting seeds. Now that I look back, I see that we should have expected that it wasn't going to be leaf mustard (Brassica juncea), the kind we crave in our salads. It turned out to be white mustard, Sinapis alba. We ate it anyway when it was young; it was better cooked as it was kind of tough and a little hairy, like raddish leaves. The trouble was that it grew a lot faster than all of our other Brassica greens, which we planted all together in a line. But we quickly gobbled it up, and now our more tasty greens can see the sunlight!


We also broadcasted a mix of alfalfa, raddish, and fennel. The fennel hasn't come to anything and the alfalfa seems to be slowly growing (though is it really Medicago sativa? We might not be able to tell until it flowers!). What grew in place of raddish, while definitely a Brassica, is not something we recognize at all. And no raddishes are forming. Again, we'll have to keep watching, unless someone recognizes this plant:

So, sprouting mixes are a cheap way of getting lots of seeds, but you must expect some surprises!

Note to Self: Plant Beans Indoors Next Year

I've been looking at the awesome blogs of people who left comments, and found that planting beans in pots seems to be quite popular: Robert does this for his peas, and Nome for her broad beans.

Our peas and broad beans both got attacked and eaten by a some kind of nocturnal rodent monster that ploughed up the lines of helpless legumes. In addition the first peas we planted didn't grow, presumably because the ground was too cold.

I never really considered planting beans indoors. My philosophy has largely been "if it can be started outdoors, better to save the space, pots and potting soil for the plants that need it". But maybe next year we'll start beans and peas indoors to get an early start. Thanks for the inspiration, folks!

Do-It-Yourself Rainwater Collection

The thing about DIY, we've been finding, is that it doesn't save you time, and sometimes doesn't even end up saving money, but you learn a whole lot in the process. So we could have gone to the store and purchased a 1000L cistern and been done, but we wouldn't have learned all we did about drilling, gluing, plumbing, and the infinite ingeniousness of water to slip through the smallest of cracks. Here's what our water collection looks like now, along with some things we learned.

Our first project was to set up water collection barrels on the doghouses (we're staying at my parents house for most of this growing season, and my mum breads dogs). We used a method we'd heard about at Earth Activist Training: slicing a corrugated plastic tube down one side and clipping it onto the edge of the roof. This worked fairly well, though it's not as easy to do as we thought it would be, and wouldn't work on a lot of roofs. It's also unfortunate that these plastic tubes, designed to cover up electrical cables, only come in horrendous colours!



Next we wanted to put our main water collection unit in the stable, right next to our garden. The water is caught off the roof in a regular gutter, and then comes in through a hole in the wall and down into a line of previously tripe-filled barrels, connected at the bottom.


This is where we did a lot of the learning (a.k.a we had lots of issues). First, it was impossible to find connectors specifically designed for this purpose (such as bungholes). Not knowing the French word for it didn't help either. So we settled for using what turned out to be the cheapest solution, using connectors designed for gas pipes.


So, here is the first piece of advice to anyone attempting to construct a similar water catchment system: make the holes just the right size. This might mean buying a drill-bit, but it's really going to save you a lot of work in the end. We thought we could skip this and make approximate holes, and then use silicon to seal it, but no. Silicon is not meant for this; it does not withstand pressure. So at first it seemed water-tight, but when the barrels filled up water started to seep through the holes (notice that the wooden support under the barrel on the left in the photo above is wet). And once it's wet, silicon won't stick, so you can't add any after the fact. In the end we got some special silicon for swimming pools, and smothered that on, but even that hasn't been sufficient yet. The leaks are very slow, so it works anyway, but in the long run it might get worse.

Another thing to think about: the overflow has to be proportional to the amount of water that comes in. I know, it's logical, but we just stuck a regular garden hose on for the overflow, and now that at last we've had a good rainstorm, the stable is flooded. Honestly, when we started working on this system, what really weighed in our minds was knowing how dry the summers are here. We weren't thinking much at all about the spring rainfall and overflowing barrrels! So yeah, remember to have a large overflow pipe.


In the end, though we got the barrels virtually for free, once you count the price of the connectors, the silicon and so on, this DIY system was far from free, or even cheap. But like I said, we learned a few things, so we don't regret it. And now we have probably a good 1500L of water stored here, to add to the 8000 or 9000L stored in other containers around the place.

We were planning to have another similar setup in another location too, but in the end this one took up all our attention and the other barrels are just outside in their raw state, waiting for us to find them a permanent location.

The Companion Planting Puzzle

So, call me the sceptical permaculturist if you want, but after my rant about mulch, today I'm going to go after companion planting. Not against the principle itself, which is great, but more on the subject of the over-optimistic and simplistic way with which the concept is sometimes approached. At times, I have myself enthusiastically and at length described the benefits of companion planting and how if you plant this plant with that plant you'll not only have an awesome trouble-free garden but you'll also save the world, and you won't even need a revolution! Hurray!

But then when you get down to it, all these pesky questions come up. How close does the borage need to be to the tomatoes in order to improve their growth and flavor? How far apart can you plant patches of calendula and still get their pest-repelling properties? How much marigolds do you need to make any difference to the nematodes? Basically, once you know what plants go together, the question becomes how do you plant them?

One thing I found really interesting while skimming through one of the myriad organic gardening books in a bookstore was that the effect of companion plants varies greatly depending on the circumstances. In "Jardiner Durablement", Jean-Michel Groult gives the example of sage, a companion to cabbage (it repels cabbage butterflies, supposedly). It grows best in a hot, well drained soil, but will give off almost no volatile chemical compounds in these circumstances, whereas it will do so more readily in moist soil, though it might not grow as well. This was really interesting to me, and it makes a lot of sense. The quality of the soil, air and soil humidity, soil pH, nutrient content and so on will all affect a plant's growth and therefore its quality as a companion.

You can start reading up on this subject and just never get to the end of it. But ultimately, I think the best advice is that of Jon Jeavons in "How To Grow More Vegetables": it's up to each gardener to try out combinations of plants and find out which ones work well in the specific context of each garden. He advises to start with combinations of few plants (only 2 or 3), in order to be able to really figure out what's going on.

I think this kind of experimentation is really very valuable, because you can't really rely on lists of companion planting combinations without testing them (and generally the planting details to make these combinations work are not mentioned). And then again sometimes you'll find that some unusual combinations will work in your particular context. In a broadcast bed we threw some peppergrass seeds and some alfalfa (among other things). The peppergrass started growing in patches where the seeds had fallen, and later the alfalfa started growing through the peppergrass. What I think happened here was that since we gave little care and little watering to this bed, the alfalfa seeds only sprouted successfully under the protective cover of the peppergrass, and the patches of bare ground where no peppergrass seed had fallen remained barren of alfalfa also. Who would have thought? Of course, to replicate this kind of thing with other plants you would really need to know the plants' growing habits well. This is the kind of thing you can only figure out by trying combinations of plants in the garden.

Has anyone out there done any interesting experiments? What combinations of plants have you found to work well in your garden?

Seedlings

At last we are getting toward the end of seedling season. As the little sweethearts get into the ground once and for all, we can finally sleep more soundly at night. No more rushing out in the evening to cover the coldframe in case it freezes, or in the morning to open them so that the coldframe-turned-solar-cooker doesn't burn our babies to cinders. No more worrying about germination temperatures, damping off, transplanting to bigger pots, etc. Hurray for spring!

Seriously, sometimes I thought our seedlings would be the death of me. For a start, we had to find a location to start them. This eventually was the bathroom, the warmest place in our largely unheated house. To help reach a reasonable temperature for seeds to germinate, we put a heat lamp over them. And this is how we got through the seedling season, doing pretty well for tomatoes, peppers, tomatillos and other nightshades, squashes and cukes.

But some plant were stubborn and simply refused to join the garden team in our amateurish setup. Bitter Gourds (Momordica charantia) and Malabar Spinaches (Basella alba) just wouldn't germinate. We ended up with one Malabar Spinach (nicknamed by Rosemary "Malibu Barbie", which probably accurately reflects the temperature sensitivity of the plant!). Not a Bitter Gourd on the horizon. Well you'll say, the most bitter vegetable in the world and a leaf veggie with mucilaginous leaves, not a huge loss. True. I'm not weeping for our loss. Just like I'm not too sad about the Snake Gourds (Tricosanthes cucumerina), which did germinate, but as soon as the weather got in the slightest chilly, and despite our diligence at covering the cold-frame at night, would drop dead one by one until we had none left. Another marginally edible squash that requires special attention and a 2 meter high trellis that we still had to dream up. Maybe it was being nice and saving us the work!

Then once they had germinated, our dear planties weren't out of the woods yet. This is when the dilemma of leaving them in the warm darkness vs. moving them to a sunny but cold window comes in. Never figured that one out. Imagine: you have a pot where you planted numerous Peruvian Groundcherries (Physalis peruviana). A couple of them start coming up. Do you leave them in the dark under the heat lamp for the other seeds to germinate, but most likely letting the early ones get tall and spindly and die, or do you move them to the window, where the other seeds will undoubtedly not germinate because of the cold?

"Damping off" is what you call it when the seedlings get all tall and spindly and thin near the base, finally collapsing or breaking off. It's caused by micro-organisms, fungi or oomycetes (that are not fungi, bacteria, viruses, plants or animals, which I can grasp, but something else entirely, which leaves me totally puzzled as to how to act toward them!). It happens most in moist, warm conditions with little ventilation. Exactly what our bathroom setup was. Our tomatillos got it pretty bad, but surprisingly they kept going, and even after having collapsed they just grew up straight again and now have nothing but a kink in the lower part of the stem to show for it.

So, I feel like I've learnt a few things and figured out what my ideal seedling setup looks like now: a greenhouse/coldframe with good ventilation, watering the seedlings from the bottom (a tray that can be emptied would be perfect), heating from below to promote root development (possibly using a hotbed with manure). Also, I'd prefer to use my own potting mix, with half garden soil and half sifted compost (as per Jon Jeavons' "How To Grow More Vegetables").

Still, how you accommodate a variety of plants with different favourite germination temperatures, I don't know. I mean, imagine you're growing cucumbers (favourite temperature: 15° to 18°C), tomatoes (favourite temperature: 20°C) , Peruvian Groundcherries (25°C), and snake gourds (25° to 30°C), what do you do? I tried putting the most heat loving ones right under the lamp and the less demanding ones further out, but still it's hard to control. And if you're using a greenhouse and/or a hotbed, then it must be really hard to control temperature. Also, does varying day/night affect germination rate?

Anyway, one thing we did get the hang of this time is to plant masses more than you'll need so you don't get a nasty surprise (which worked except for the plants that just plain refused to germinate -- cowards). Now the trouble is we can't bring ourselves not to plant any of them. I guess it'll take another year or a few to get the hang of thinning and selecting plants. But hey, one thing at a time.

Hugelkultur

As we're all for trying different things, we've set up a test Hugelkultur mound. The idea of Hugelkultur, a German technique, is that you bury woody wastes under your bed for them to rot down and enrich the soil over time. We had a lot of alder roots that were lying around from when an alder was dug up. Alder is a nitrogen fixing tree, so it should bring a good amount of nitrogen to the garden, but it also has a reputation for not rotting, a reason why it is chosen for making posts for use in waterlogged or even submerged areas. So I guess we'll see if it was a good choice or not!

Our method was very basic, as you can see in the pictures. We just piled the roots in a shallow hole, then added manure, earth and compost on it until it was covered. We'll be planting squashes, and possibly beans and corn in this bed.

Mulch

Hello world, this is Chris, here to deliver a daily dose of permaculture existential questions.

There are many things that seem simple on paper in permaculture. Mulching is one of them. The theory goes: you throw a copious layer of dried plant material (straw, shredded bracken, pea straw, grass clippings, alfalfa straw, coconut husks, woodchips, etc.) on your garden bed, and you will have solved many of the most preoccupying problems of the average gardener: you prevent water loss through evaporation, nutrient loss and erosion from rain, wind and heat, inhibit weed growth, and boost microbial and invertebrate life in the soil. And if you want an even longer lasting mulching regime, you can go for sheet mulching and spread a layer of cardboard or newspaper, then a layer of compost or aged manure, and then a layer of brown plant material, and this should be even better at banishing drought and weeds and boosting fertility in your garden.

Wouldn't it be nice if it were that simple! But there are some pitfalls to know about. The first is that a thick layer of mulch means that the soil is going to take longer to warm up in the spring, so you may want to rake your mulch to one side when the sun is shining to help the ground warm up. Of course that's tricky if there are lots of perennials in the bed. This might be a reason why our peas and broad beans didn't come up for the most part. One sunny, circa 15-20 degrees Celsius day, wondering if they were on their way, I stuck a finger in the ground, and sure enough it was really cold right under the sheet mulch (that I had installed when the ground was still cold). I hear that cold ground is a common reason for peas not coming up (these guys have a solution).

Next, I wonder how you can reconcile planting seeds directly in the ground and sheet mulching. Planting perennials in mulch or sheet mulch is fine, but can seeds push through mulch? Probably not, since that would put in question the weed suppressing properties of mulch. So should you wait until your seeds have come up, and then put mulch between the plants? I have tried several different tactics here. I have sheet mulched, then made gaps in the top layer of dry plant material, and planted seeds in the layer of soil+composted horse manure above the cardboard. This has worked for lettuces, I guess their roots made it through the cardboard below. I've also tried planting seeds in bare ground, and then mulching in between. It becomes impossible to sheet mulch in this case, but spreading some brown much material among the plants is easy enough. Is it enough to suppress weeds and do all the other magical things mulch does? We shall see...

One thing I have noticed is that a thin layer of mulch thrown on top of direct sown clover seeds made a huge difference. I just threw the clover seeds on the ground without burying them, which meant that when the sun shone and the earth dried out, the seeds would sit there and refuse obstinately to germinate. Areas on which I had half-heartedly thrown a thin layer of mulch, however, where full of tiny clover seedlings. So, among all my questionings of the value and appropriate use of mulch, this is my one shining success story! In fact, I have taken to throwing a thin layer of mulch material on the seedling beds, and do believe this to be better than bare ground, while not inhibiting seedling growth.

So, mulch can delay soil warming in the spring, and has varying impacts on seedling. But it gets even more technical if you look into it. Some mulches compact down in the rain, forming an impervious mat that prevents water infiltration, while mulches can absorb all the water from light rainfalls, and then evaporate it back into the atmosphere, leaving the ground below dry. This means that mulching is not necessarily a water saver, but can actually be a water waster! I have noticed this when I watered the mulched beds copiously, and then stuck a finger in them only to find that below the soaked, spongy mulch, the ground was bone dry.

In addition, uncomposted, green mulches, especially uncomposted wood chips, contain phytotoxins and hormones that inhibit plant growth. They also tie up nitrogen, and can starve the plants. Doesn't sound too great... Anyone out there going to take a stand for green mulching?

Lastly, there is the question of how deep to plant perennials in mulch, especially sheet mulch. Should the top of the root ball be level with the cardboard, the compost, or the straw/clippings? If the plants are too deep, the mulch around the stem can favour fungal diseases and crown rot, while planting them too high will make their root ball more likely to dry out.

So, I guess this is what happens when you take your head out of your books and try things out for real. You realize things aren't that simple! At least, that's what I'm going through right now, and I often feel confused. What would Bill Mollison do?!

Our mulching has been done with dead bracken we pulled up in fields, and shredded with a weed wacker. Apparently it's high in potassium, making it especially good for things like potatoes. On the other hand, it grinds up pretty fine, which makes it more likely to form a dense mat with less air flow. Maybe we should try mulching with unshredded bracken to see if that would make a more fluffy, porous mulch.

In permaculture, you live and learn. Nothing can replace direct experience and experimentation. Hopefully I can figure out the intricacies of mulching, and I'll be sure to keep you posted if the universe teaches me anything more on the topic.

For an interesting discussion on the impacts of different mulch types, you can read this. Also for another practical account of mulching strategies and lots of great advice, check out this post on Patrick's blog.

PS: So I think I was a bit down on mulch when I wrote this. I must say that we've just had a dry period of a few weeks, which just ended, and I really noticed the difference between sheet mulched beds and bare beds. We barely watered the perennial cabbage/leeks/walking onions bed, which is sheet mulched, whereas the greens and broadcast sown beds, which aren't, required daily watering. Also, I can now vouch for the weed suppressing properties of mulch. So In short, sheet mulching is awesome, especially for planting seedlings later in the spring once the earth is warm. In other cases, you just have to give it some thought. But I like giving thought to what I do in the garden, so that isn't a problem, is it?