|Deep mulching produces a bounteous harvest!|
|Mulching feeds your "micro-livestock"|
In these first years of establishing new garden sites in Alpine and Monroe, we also have used a high-quality organic fertilizer, our own worm-castings compost, and rabbit and llama-doo applied judiciously to the plants that need a boost. But we don't apply any single concentrates of nutrients such as lime or gypsum as we have found through years of gardening experience that a garden's soil can get seriously out of balance through the application of these concentrates.
A summary of the benefits of "deep-mulching":
- Keeps moisture in (less watering). Though when you water, you must water long and deep to be sure the water penetrates down through the mulch and into the soil. In our Monroe garden, we have gone over two weeks without watering in the heat of August but we watered each section of the garden for over two hours at the beginning of those two weeks. When you're first planting a bed - with seeds or transplants, you need to water more often till the plants are established. To check if you need to water, lift mulch in the paths and check for moisture level in the soil. You can often see red worms and tiny rootlets extending from the plants growing in the beds.
- Keeps weeds down.
- Balances your soil-nutrients (your "micro-livestock" keep things balanced without you having to figure it all out.)
- Moderates day/night temperature fluctuations in the soil.
- Adds organic matter to keep soil from becoming too sandy or clay-bound.
- It's very comfortable to sit or kneel on as you cultivate and harvest your plants. (We had a photographer come to our gardens once and said it was "the most comfortable" garden she'd ever been in!)
What materials make good mulch? It is best to choose materials that are readily available in your local area. Urban gardeners may find that leaves and grass clippings are easiest to come by.
We love leaves! Many cities will actually dump a load of leaves for personal use if you have an adequate drop-site. Do be aware that you can't be 100% sure of the kind of leaves you're getting. There is also likely to be some residue from oil and other materials from motorized vehicles (though probably not enough to be very concerned about). You'll need to be sure and use good gloves in distributing city-leaf piles as its possible that broken bottles or other sharp trash could be mixed in.
|Leaves we collected from Alpine Park|
In some years we have applied the leaves on dormant beds in the fall so they can decompose in time for spring planting. Other times we have stored leaves in rings we crafted from fencing, or just made a deep pile and tarped it for the winter. This latter option produced very rich, yummy, decomposed leaf compost by the following spring. We have also layered leaves and fresh grass-clippings in these rings which also makes a great mulch.
|We love maple leaves!|
|Maple leaves make excellent mulch|
Hay! Hay! Hay! If you live in, or near the country, straw and spoiled hay make a great mulch. Straw is the baled stalks from grain crops (wheat, oats, barley) after the grain has been harvested on top -- typically used for bedding. Straw has a lower nutrient content than hay bust also, usually fewer seed (so not so many weeds to deal with later-on). Hay is typically the stems of grasses after their seed-heads have been harvested.
Many farmers have hay from previous seasons that has become wet or moldy or otherwise unsuitable to feed to their livestock. They will usually be glad to have you haul it away for free, or very little per bale. If you don't have a trailer, you might be able to arrange for the farmer to bring it to you if you give him or her something for their gas and time.
Another rural source for excellent mulch is to clean out the stalls of goats, sheep, cows or horses. (Note: un-composted horse manure can be full of herbicides which are toxic to many flowers and vegetables - especially tomatoes and peppers. See our articles about this issue here and here.) It's ideal if their bedding material is straw. If wood chips or saw dust is their bedding, you'll only want to use it if its been composting for a year or more. The heavy balance of carbon in the wood-products can actually pull nitrogen from your soil. Also if you are using horse manure, be sure it has thoroughly composted for at least a year so that all grass seeds are no longer viable.
|A delivery of spoiled hay|
When to mulch? In the cycle of a year's gardening, there are two main times for a mulch "push". At the end of harvest, when you're putting your garden to bed, if you have a large enough quantity of grass clippings, raked leaves or animal bedding from cows, goats, sheep or horses that has manure mixed in, you can apply this liberally and roto-till it into the ground. This gives you the whole winter for the micro-livestock to digest it in time for spring planting. It is not a good idea to apply, and till your mulch into the ground in the spring time because the "browns", the more woody/cellulose aspects of the mulch that are high in carbon will bind with the nitrogen in your soil and effectively rob it from your spring seedlings if tilled in too close to their planting.
The second cycle of mulching begins in the spring and continues throughout the summer as you plant your garden rows. This includes deep applications (6" or more") of hay or straw flakes in the garden paths. This provides comfortable and attractive paths to walk on and tend your beds. It also slowly feeds the micro-organisms in your soil and keeps moisture-levels and soil-temperatures at a more constant level.
You can also till in fresh grass clippings and combinations of grass clippings and leaves directly into garden beds as long as you wait 10-14 days for planting. See this post on the methods we use.
If you're using all that hay and grass clippings, what about weeds? This is a question we get asked a lot. Bringing a whole bunch of hay into your garden may not seem like a good idea as you also bring a bunch of weed seeds that can then germinate in your garden soil. The key is in applying enough mulch, soon enough.
How much is enough? You want to put enough of the material to keep in the moisture and block the sun from reaching any weeds growing in the paths. Hay bales often naturally break into "flakes". Just lay these in your paths, end to end, without fluffing them (which can scatter seed into your beds) and make it easier for weeds to grow through (5" to 8" is ideal). If you're using dried leaves, they too should be about 6" thick. Grass clippings work best if you put them locally around the base of plants (leave about a 2" gap around the stem of the plant as the grass can literally burn your plants if it is applied thick while still green). When applied liberally in the paths they can form a gooey surface that can be quite slick and dangerous to walk on. They also become "felted" or matted down making it harder for water to seep through to the plant's roots. You'll be amazed to see, over the course of a year, that the 8" of mulch you applied in May, June or July, will be almost totally digested (from below) by the following March/April when you begin the spring plantings. Worms travel up to the surface of the soil at night and feed on the mulch, carrying it back down into the soil in their gullets and distributing it as castings throughout your garden.
You will rarely find exposed, bare soil in Nature unless there has been a recent disturbance such as a fire or landslide. In our gardens we try to imitate nature, leaving as little bare soil as possible. Bare ground makes it very easy for weed-seeds to take hold.
|Alpine Garden - 10 weeks after breaking ground 2009|
- Municipal leaf-gathering
- Raking your own (offer to rake your neighbors' in exchange for keeping the leaves.)
- Farmer's moldy or spoiled hay
- Set up your own collection site: Rural transfer stations appreciate any solution that keeps material out of the landfill. Below is a picture of a collection site Chris established near his farm in northern California.
|A gathering site for mulch donations at the local, rural transfer station.|
|Another example of how the garden looks--fully mulched--with hay.|
|Tilling in leaves in the fall - so they have time to decompose by spring.|
|The potatoes were mulched first with leaves and we're adding oat-straw in the picture.|
|This was a "lawns-to-gardens" project where we simply scalped the grass from the beds and mulched the lawn path-ways. The plastic on left was placed to "solarize" the grass (kill it in preparation for fall-crop planting).|
|Here Chris is using lettuce that has "bolted" (gone to seed) as mulch in the potato patch. Oat straw was then placed over it.|
|Fun in a leaf ring! (Robin, Chris' son in a "nest" of leaves 1996)|
Herbicide Contamination in Manure, Compost and Grass Clippings?
Grass Clippings and Leaves for Mulch
Mulch We Love, and Why
Preparing Garden Beds - One Low-Tech Way