The Benefits of Leaves in the Vegetable Garden

The forest floor is a thick layer of healthy soil that is rich in nutrients thanks to the leaves that fall each year. The dense mat of slowly decomposing leaves builds soil, improves air and water retention, provides food for plants, and creates a great environment for earthworms and microorganisms. We can mimic the natural soil building process by adding leaves as fertilizer, leaf mold and mulch to our gardens. Instead of throwing these leaves away, use them in your garden to improve the health and texture of your soil.

Add the leaves as "brown" or carbonaceous matter to your compost pile, trash can, or trench to create a nitrogen-rich plant food. As a general rule, you want your carbon and nitrogen ratio to be in a balanced 50:50 ratio. Chopping the leaves will pull them off the carpet and speed up the decomposition process, as will stirring the pile regularly. Leaf rot is low in nitrogen, but the addition of humus is unparalleled in builder's soil. Leaf mold can also be used with great success in potting mixes. Fall leaves can be mulched deeply (2-4 inches) in your garden and used around perennials, between vegetable rows, or as a soil protector in winter.

Leaves are a free gift from nature given to us every year. Since we collect leaves every fall, let's look at how you can use leaves to improve the soil in your vegetable garden:

compost leaves

paper template

Mulch with leaves

compost leaves

Leaves are a great source of carbon to add to your compost bin or pile. A healthy compost pile is a mixture of brown and green matter. In general, dead, dry organic waste (such as leaves and straw) is high in brown matter, while green matter is recently alive and high in nitrogen, such as kitchen scraps or freshly cut grass. Soil microorganisms use decomposing material at a rate of 30 parts carbon for every 1 part nitrogen, so you want to balance the brown:green ratio for healthy decomposition. Although microorganisms need a 30:1 ratio of carbon to nitrogen, this does not mean that 30 times more brown matter should be added than green. You want to mix brown with green in a 1:1 ratio. The brown stuff contains much more carbon than nitrogen (in the case of leaves, 60 to 80 times more carbon than nitrogen) and because green organic waste also contains significant amounts of carbon. Here is an excellent website that goes into detail about the carbon-to-nitrogen ratio in compost.

The ratio of brown matter to green matter also affects the temperature of the mound and determines how quickly the compost will decompose, and again a 1:1 ratio is ideal. If there isn't enough carbon, the compost will become excessively wet, mushy, and smell of ammonia. If there is a lack of nitrogen, the compost will dry out and not heat up enough, resulting in poor decomposition. Fresh fallen leaves contain more nitrogen than old dry leaves.

Compost is an aerobic decomposer, which means that the microorganisms at work thrive on oxygen, so the pile must be aerated for proper decomposition. The core of the mound keeps the temperature rising and the decomposition process continues.

Hot Compost

Cut the leaves. This step is not necessary but will greatly speed up the process. The easiest way is to run a lawn mower on the leaves (attach a mowing bag if possible), but you can also buy small leaf cutters. You can also mow leaves with a weed eater in the litter box.

Fill your compost bin with alternate leaves (and other brown materials) at a 1:1 ratio of green organic waste.

Turn the compost at least once a month, but turning the pile every week will speed up the decomposition process.

Plant in the garden. The leaf compost will be ready when it is fragrant, thick and thick. It's always a pleasure to deal with the fresh, rich humus that comes from the compost bin. This can take anywhere from 6 weeks to 6 months depending on the shift schedule, formation, and even the weather. 

Cold Composting

It's made like hot compost, except you don't turn the pile over. If you're anything like us, turning compost doesn't always make it to the top of your "to-do list" and your compost pile is slowly shrinking on its own. Cold composting is relatively painless, but it has some drawbacks:

It may take a year or two before the compost is ready to use.

During this time, many nutrients can leach out of the compost and be lost to the soil below the compost bins.

Depending on what you put in your pile, it can turn into moldy dirt or dry rot.

All that aside, cold composting is much better than no composting at all. We've had great success with cold composting year-round. If you don't have time to run your own compost bins, consider getting a hog!

Trench composting

My favorite composting method is probably trench composting, and leaves work very well for this method. The idea of trench composting is to dig compost directly into the garden and let it slowly decompose underground.

Cut the leaves. Again, this step is not necessary but will help speed up the decomposition process. Run a lawn mower over the leaves or use a commercial leaf shredder.

trench digging; You can prepare a long trench if you want to fertilize a lot at once, or you can dig a small hole as needed. Dig a trench with the vegetables you're growing because you don't want to plant directly on top of the compost because that could cause the roots to rot along with the compost.

Add your leaves and other organic waste to the bottom of the trench in a brown:green ratio of 1:1. When the trench compost leaves, it's best to add more green material rather than less.

Fill the trench with soil, burying leaves and other materials. The trench can be mounded slightly as it will sink from broken leaves and other materials.

Now your compost directly feeds your vegetables and improves your soil. Below is an article that goes into more detail about trench composting.

Can I add freshly fallen leaves to my garden? In small amounts, it is okay to dig up the leaves directly into your garden as they will slowly decompose in the soil and produce humus and food for your plants. However, adding large amounts of leaves is not recommended. Remember that the microorganisms responsible for decomposing leaves use 1 part nitrogen for every 30 parts carbon, yet dry leaves contain about 80 times more carbon than nitrogen. Microorganisms will consume the nitrogen in your soil to replace it, and your soil may be depleted of this essential element. Some people refer to this as saying that leaves "fix nitrogen" in the soil.

Leaf Mold

Leaf mold is probably the best way to add hummus to your garden. Although the name may sound somewhat ominous, mold refers to the fungi that cause this very beneficial process.

Leaf mold is an anaerobic decomposer and uses different microorganisms than compost. The microorganisms involved in leaf mold formation do not require oxygen but thrive on nitrogen. For this reason, leaf rot is a great source of humus but not a food source for your plants. Leaf rot benefits your garden soil by improving soil structure, aeration, water retention, and loosening the soil. Leaf mold also works great as an alternative to algae compost.

Natural Alternative to Peat Moss Peat moss is a popular soil amendment, especially in a potting mix. However, there are many environmental concerns about algae harvesting and the fact that thousands of years old peat bogs are being stripped in very destructive ways. Leaf mold is a great alternative to peat moss, and is sustainable, renewable, and environmentally sound.

Leaf mold may take a year or two to decompose, but it is very easy to make. Here are a few different ways to create a leaf template for your vegetable garden:

Paper mold stack

Collect the papers.

Put the papers in a pile. Instead of a pile, you can make a small cage with several poles wrapped in chicken wire. Attach the leaves to the cage.

I am waiting. Leave the mound undisturbed for a year or two, and the leaf mound will turn into quality humus.

Make a leaf template in a trash bag

You can also make a leaf mold in a large plastic garbage bag. This process is faster than turning it into a pile, and it usually takes about 6 months to fully decompose, but you need to be mindful of the potential harm of introducing plastic into your vegetable garden.

Cut the leaves. It's not necessary, but running over your leaves with a lawnmower first will help break them down faster.

Fill a large trash bag with leaves.

Gently wet the leaves and seal the bag.

Cut some holes or slits in the bag to allow air to flow through.

Change the leaf mold every week or so by shaking or rolling the bag.

Moisten the leaves as needed. Every month or so, it may be necessary to add a little water to keep the leaves moist.

Add it to your garden at about 6 months when leaf mold has completely decomposed.

Mulch with leaves

The leaves make an excellent mulch or top dressing for your garden. Leaf mulch will kill weeds, retain moisture, maintain soil temperature and prevent soil erosion in winter.

Although tilling leaves directly into the garden can deplete the soil of nitrogen, this is not a concern for mulched leaves. Leaves used as a top cover will slowly decompose and be added to the garden at a rate the soil can naturally handle.

Plant about 5 to 10 cm (2 to 4 inches) of leaves in your garden bed. They can be placed along paths, between rows of vegetables or around perennials. When mulching plants, do not bury leaves on top of the plant as it can make the soil too wet and rot the plants. You can either cut the leaves off or leave them whole. Shredded leaves will decompose and enrich the soil faster, while whole leaves will suppress weeds and retain moisture better.

The best leaves for the garden

Not all leaves are created equal, and some leaves are best used in your garden. All leaves naturally contain lignin, which prevents decomposition. Leaves with low lignin content decompose rapidly such as poplar, maple, ash, fruit tree leaves, and willow.

Leaves of oak, birch, beech, and sweet chestnut contain more lignin and take longer to decompose, but are still excellent additions to the vegetable garden.

Acidity of leaves and soil

The pH of fresh leaves is usually less than 6.0 and can make the soil more acidic (low pH). However, when the leaves decompose into leaf mold, or compost, they become nearly neutral.

Over time, leaf mold will help neutralize the soil whether it is acidic or alkaline.

Trees for the Garden

As a child, my mental image of a vegetable garden was a mixture of vegetables, trees, fruits, and flowers that was as beautiful as it was functional. However, when I planned the first acre garden, that image was somehow replaced by a flat patch of vegetation with perhaps a few fruit trees pushing the outer edges.

The modern concept of a vegetable garden is row after row of vegetables, but this horizontal view of the garden neglects to include the three-dimensional aspect of nature. We are often led to believe that trees in the garden will block precious sunlight from reaching our vegetables, yet plants that need "full sun" need 6 to 8 hours of sun each day, thrive with light, and the rest they can take. Break under the branches of trees.

Not only does adding trees to our gardens make use of “unusable” space, but it also eliminates the monotony of monocultures, reduces erosion, improves water retention, and creates biodiversity. It also provides us with a valuable source of soil fertility. Or in the case of Leaves, right above our heads.