Cover crops

Cover crops, also known as green manures, are crops that are grown and then intentionally tilled into the earth.  Though they’re not harvested, they benefit gardens in multiple ways:

  • They improve the soil by drawing nutrients up to the surface, where they become accessible to later crops through the compost that results after they’re tilled.  Mowing the plants and letting the cuttings dry for a couple of days before tilling them under lengthens the time it takes for the vegetation to rot, therefore making their nutrients available longer.
  • They protect the soil when vegetable crops aren’t being grown–they limit the spread of weeds, and prevent the soil from drying out in the hot sun or eroding away nutrients in the rain.
  • Their deep roots aerate the heavy soil and make it easier for future crops to also grow deep roots and access the nutrients they need.
  • Legume crops convert nitrogen from the atmosphere into a soluble form that future crops can absorb.
  • They increase the amount of microorganisms in the soil.  These help decompose the organic material and make nutrients available to future plants.

Fall cover crops are generally sown about a month before the last frost date.  Here are a few options for cover crops to plant that do well in the cool fall weather that is on its way:

  • Alfalfa
  • Barley
  • Fava, broad, or pinto beans
  • Clover
  • Cowpeas
  • Fenugreek
  • Oats
  • Rapeseed
  • Soybeans
  • Vetches
  • Winter rye
  • Winter wheat

Ensure that you turn your cover crops under when they flower, but before they go to seed, so that the crops will not reseed themselves in the spring.

Composting 101

Most Canadian municipalities now offer curbside collection of yard and kitchen waste.  Some even allow you to pick up free bags of compost in late spring.  So why make your own compost onsite?  Aside from avoiding the costs associated with purchasing compost, you can control what’s feeding your plants.

Composting kills many of the weeds, seeds pests, and diseases that may be present in your food and garden waste, but it retains most of the nutrition.  It’s recycling at its finest!

But compost stinks, doesn’t it?  And it attracts maggots?

You can avoid having stinky and maggot-infested compost by excluding animal products (meat and dairy) from your compost.  Eggshells are fine.

Many of the commercially available compost containers are made of plastic, which contains vents but are not very breathable.  The compost does tend to smell when you open the lid.  Once the lid is closed, they’re usually fine.

If you place your compost in a container made of wood or other natural materials that are spaced to allow air flow, and add grass clippings or other yard waste over any particularly fresh kitchen scraps, it should not smell.  You may also want to avoid using manure as an activator (see more in hot composting, below).

But I don’t have a backyard

Worm farms are great.  The worms can’t eat all of your compost, but they can eat some of it.  They’ll create beautiful dark earth for you.  They don’t smell and you don’t need to take them for walks.  You may be able to purchase worm farm kits locally.

Types of composting

There are two main types of composting: cold and hot.  Cold composting is basically the “throw in what you have” method.  The compost does not heat up enough to cause rapid decomposition, so some weeds seeds may not be killed, and the process takes longer.  Hot composting is like making a lasagna; you have to have enough ingredients on hand to make one set of layers, because you don’t want to cook it with the sauce on the top.  If properly assembled and monitored, it will typically produce compost in two months rather than the year or more needed for cold compost.

The specific details of how much material you should add will vary according to the type of container and composting you choose.  As always, what follows are guidelines.

Cold composting

Cold composting is the easier option, and it also produces more fertile soil than hot composting, because the material does not get hot enough that all of its nutrients are broken down.  Some are retained and then released when the compost is added to the garden.  Worms find their way into the compost to help break down cold compost material.  To accelerate decomposition, consider cutting materials into small pieces.

The layers are simple:

  1. On the bottom, add sticks to let ait infiltrate the compost.
  2. Follow this by garden waste, grass clippings, and kitchen waste as they are produced.
  • You can add straw, or straw-like plants, to aid with air circulation.
  • You can add manure to the compost to act as an activator to increase heat (and therefore the rate of decomposition).

Once or twice a year, turn the pile to improve decomposition.  I use two side-by-side wooden compost bins, so I turn them in the fall once the garden is almost empty, and often in the spring.  One bin contains last year’s compost, and the other one contains the current year’s compost.  Both are at least half full when I turn them.

Turning does not involve rotating the bins, but its contents. I transfer the intact plant material from the first bin to the second, removing the composted dirt and putting that in the garden.  Then I move the intact plant material from the second bin into the first bin, adding a bit of composted dirt between layers, and move the rest of the composted soil from the second bin to the garden.  I am left with one full bin of rotated compost and another that is empty and ready to accept new spoils.

Hot composting

Hot composting relies on manure to heat compostable materials up so that they break down quickly and thoroughly.  Roots and woody materials are thoroughly broken down, and weed seeds and diseases destroyed.  Hot composting is not an ideal solution for small lots because when manure is exposed to high temperatures, ammonia is released into the air.  In other words, it can be smelly.

The layers are more complex.  You must complete steps 2-5 each time you top up the compost.

  1. On the bottom, add sticks to let ait infiltrate the compost.
  2. Add 4-6 inches of rich green organic matter, such as grass clippings and kitchen waste.
  3. Add 1 inch of cow, sheep, or horse manure.
  4. Add 1 inch of soil.
  5. Add 4-6 inches of brown organic material, such as straw.
  6. Repeat steps 2-5, ensuring that 5. is always on the top.
  7. Once the material has begun to decompose, don’t add any additional layers.  Check the temperature, which should be between 54C and 60C.  If it gets waterlogged, cover it with a waterproof tarp.  If it is too dry, water it.
  8. When the temperature drops, turn the pile.
  9. Repeat the process until it is decomposed.

Seed starter

You can use your compost to create soil to use to start your seeds.

Remove some of the compost you created, and set it in a pile for at least a year.  Store it in cloth or burlap bag for the winter in a cold room or root cellar so that it retains its moisture.  You may wish to run it through a sieve before you use it to remove any sticks or large particles.

The good stuff

As a kid, at least once a year we were visited by my great aunt, who would arrive at the farm with several burlap bags and a huge smile on her face. She’d rub her hands in excitement about receiving what she called “the good stuff.” To the uninitiated, the good stuff was the beautiful black earth that had spent a year or so cooking its original ingredients, which were mainly cow manure and straw, with some wood shavings, horse manure, and sheep manure thrown in for good measure. Now, as an adult, I know why she was so excited. It’s almost impossible to find the good stuff on the market.

The dirt

Manure has been called the “black gold” of the gardening world. It contains a rich and wide variety of minerals and nutrients, and provides abundant amounts of the three chemicals your plants need the most: nitrogen, phosphorus, and potassium. It improves the condition of the soil so it is better able to hold moisture, and it promotes better root growth.
Composted manure can be purchased from your garden centre, or you can compost your own if you know (or are) a friendly famer. You should never use it fresh, because it can damage your plants. Add composted manure to your garden in the fall.
Rabbit manure is the best for gardens, followed by sheep and goat manure, then cow and horse manure. You may find the selection at your local garden centre limited to sheep and cow manure.

Leaf mold

If you don’t have access to manure, you can enrich your soil using leaf mold. In the fall, rake up your leaves and place them in a wire bin. Keep the leaves damp, at least until winter takes that process over for you. Fungus will break down the leaves into leaf mold, which you can use as mulch or mix into the soil, depending upon whether the leaves have partially or completely decomposed.

Liquid organic feeds

Liquid organic feeds are useful for container gardening, and when you notice that a plant is not doing well. Ideally, the earth should be sufficiently fed with compost before sowing so that it is not necessary to supplement your plants.
  • Compost tea: Put a cloth bag of compost that has reached the finished stage (is rich, dark, soil) into a bucket or garbage can full of water, and leave it for a few days. Apply the compost as mulch for the garden, and water down the tea until it is the colour of weak tea before applying it to your plants. It may burn them if it is too strong.
  • Fish emulsion is an all-purpose fertilizer, which contains nitrogen, potassium, and phosphorous. You can buy it at your local gardening centre.

Fun fact

Apparently, bird manure is the most valued of all. In the Middle Ages, many Europeans kept pigeon lofts on top of their houses, eating the birds and using the manure to fertilize gardens and fields.
We’ll talk more about composting plant matter later.