Posted on

Mulch Research Report: Mulching Your Garden

diffrent mulching materials

diffrent mulching materialsAll gardening experts agree that mulching your garden around plants and bare ground is the most important step in creating a low maintenance vegetable garden. Mulching is a simple process that suppresses weeds, prevents the soil from drying out to fast, prevents erosion, reduces the compaction of soil, moderate ground temperature, prevents mud from splattering, increases the nutrients level in the soil, increases the populations of beneficial soil microbes and earthworms and – let’s not forget – makes your garden look prettier and well kept.

When to Mulch

Mulching should be done every year in spring time just about when the soil starts to warm up, which depends on your climate. Some gardeners, especially ones living in colder climates mulch in autumn so the mulch would prevent the soil from thawing and freezing during winter. Besides regular once-a-year mulching, you should add much immediately after disturbing the soil, meaning after planting. If you have a bare ground patch in your garden, you can put mulch on it any time.

How Much Mulch

At the beginning start by putting around 1-2 inches of mulch if your garden has a layer of compost on top. If you haven’t used compost, you can add around 2-3 inches of mulch. In any case, the mulch will break down over time, so you should add it when needed. But don’t go overboard! Too much mulch (more than 2-3 inches) is too much, it will harbor pests like slugs, prevent the soil from warming up in the spring and keep out moisture from watering and rain. Only in very sunny spots you can use more than 3 inches of mulch, if really needed.

How to Mulch Your Garden

Start by removing all the weeds, grass, and other unwanted plant material. Then loosen top of the soil which will at the same time incorporate what’s left of old mulch (from previous year) into the ground. Water your soil well and then start adding mulch but never pile it up against tree trunks or plant’s stems. Insure that the mulch isn’t touching the stems and that there is no mulch on top of (lower) plants and on leaves.

Types of Mulch

There are all kinds of material which can serve as mulch, and I will address each of them further in this article. Some types of mulch are preferred for vegetable gardens, while other (like bark or pebbles) are used almost always in flowerbeds, shrubs and pathways. If the nutrients levels in your soil are in desired range, you can use any other organic material which you fancy. If you soil needs more nutrients, adding nutrient-rich, fast decomposing mulch material (like compost and leaf-mold) is a great way to improve your soil at the same time while protecting it.
Be careful which type of mulch you use around your plants, since some types like shredded wood chips use nitrogen from the soil while they’re decomposing. Pine needles and leafmold should be find, but don’t make your layer higher  than inch or two. Bark chips are better choice, but they come at a price.

compost mulchCompost isn’t very suitable as mulching material. Compost is generally speaking animal waste product that has been decomposed entirely and looks like a bit like coffee grounds. Compost is a rich source of nutrients, so if your garden soil needs them, try to get your hands on some compost. The problem with compost when used for mulching is that weeds love it, and wind blown seeds thrive on it. The only way would be to top the compost with other mulch material on it, organic one proffered.

grass clippings mulch
Grass clippings. Great for vegetable gardens, especially if dried first. Just don’t use the grass that was treated with any kind of herbicide! Grass is great mulch, since most of use have it in our front lawns or garden, hence it’s free! Although grass decomposes quickly, don’t put more than 2 inches or it will mat down and prevent correct watering of the soil.


hay mulchHay. Avoid using hay as mulch material if possible. Unlike straw which has only the stems of plants, hay has seedhands which can sprout into weeds in your garden. If you do use hay, make sure it’s weed and seeds free, otherwise you’ll make trouble in your garden. Never pull straw or hay up to the stems of your vegetables, or you’ll have rodent and slug damage.


Leaf Mold MulchLeaf mold are old leaves from trees and plants, chopped or shredded and aged. It’s not often sold, but you can make leaf mold yourself, it’s quite easy. As a mulch, leaf mold is one of the best – nutrient high and excellent soil amendment. Shredding leaves will not only make them a prettier mulch, but will also speed their decomposition. Earthworms love shredded dried leaves, and turn them great fertilizer. The “no more that 2 inches layer” rule applies here.


leaves mulchLeaves. If not shredded first, leaves aren’t a really attractive mulch material. They don’t look attractive and can get be easily blown away by wind. Also, in colder climates, leaves are easily matted and could freeze into blocks of ice, damaging your plants instead of insulating them. If you have access to sufficient quantities of leaves, you can shred them and make mulch using simple rotary mower (just run them over). Don’t use fresh leaves if you don’t know what you’re doing, because some sorts (like Oak) are acidic when fresh. Spread shredded leaves in 2 inches layer.


newpaper mulchOld newspapers. Or new ones, if you prefer. 😀 A three or four sheet layer of newspapers is very effective mulch, when it comes to suppressing weeds. Don’t use slick paper or colored newspapers since the colors can contain lead or other heavy metal. The problem with newspapers as mulching material is that you need to wet it down and cover with another layer of heavier material, like bark chips.


pine needles mulchPine needles decompose slowly, but during decomposing process they can deplete the soil of nitrogen if used in excess. But don’t worry, 1 or 2 inches of pine needle mulch won’t change the pH levels of your soil. The acidic nature of pine needles makes them not the best mulching material for plants that don’t like acid soil. You can use them on paths or play areas, or around plants in thinner layer.

Sawdust and other wood chip material area a huge drain of nitrogen during their decomposing process.

hay mulchStraw. Straw is a great, cheap mulch for vegetable gardens. They aren’t attractive, so people avoid using it in flower gardens or need the house, but in vegetable gardens they are great source of nutrients. Straw breaks down quickly and won’t mat down like grass or leaves, so you can use a much thick layer that most other mulches (6 or 8 inches is fine). However, if you live in a rainy climate, avoid using straw since it will rot if always wet.


Bark is good looking and breaks down slowly, but because its moderately expensive it’s not suitable for vegetable gardens.

Dyed mulches made from pallets or other waste wood should be avoided in vegetable gardens due to the fact their dyed (albeit with non toxic colors).

Gravel and rocks. Perfect for flower gardens, paths or play area but since they don’t improve the soil not recommended for vegetable gardens.