My Lawn is My Garden’s Best Friend
Many people believe lawns cause more harm than good. Gas-guzzling lawn mowers spew both air and noise pollution into your neighborhood, and fertilizers and herbicides contaminate the soil and water. I agree with some of these complaints – many people have lawns that are far too large, use too many chemicals, and have no tolerance for a healthy variety of plants or wildlife in their lawns.
But I have come to love what my lawn has to offer my gardens. Lawn cuttings are one of the very best mulches for my garden. Why do I say “lawn cuttings” instead of “grass cuttings”? Because my lawn includes a variety of plants, including clover, plantain, dandelion, grass, and more. And cuttings from all of those plants help to fertilize my garden, reduce how often I need to water, keep my soil soft, and prevent a lot of weeds from growing.
Lawn cuttings are rich in natural nitrogen and other nutrients, and help to fertilize your garden. Mulch produced from a great variety of plants in your lawn offers a greater variety of nutrients for your garden. Every time it rains, the water slowly leaches nutrients from the mulch into your soil. As the mulch decomposes, it adds organic matter and more nutrients to the soil.
In addition, earthworms absolutely love lawn cuttings. When growing conditions are moderately warm and moist, I have seen this type of mulch disappear into the soil at a very fast rate – as much as 1″ of mulch in 4 weeks. The worms leave very fertile worm castings behind, and help to create soft soil.
The small lawn cuttings are easy to fit around vegetables planted close together in raised garden beds. If you collect cuttings when there are few weeds going to seed, lawn cuttings don't significantly increase the weed burden in your gardens (unlike most hay and straw these days). Mulch prevents many weed seeds from growing, and any surviving small weeds are very easy to pull out of the soft soil.
Mulch protects the soil surface – it keeps the surface of the soil loose and open, allowing rain and air to easily penetrate into the soil. Plant roots and soil life need fresh air to thrive. Bare soil exposed to sun and weather can quickly become hard and dense.
Mulch helps to reduce water loss, and decreases the amount of watering needed. Being a very finely cut material that packs closely together, a modest 2″ thick layer of lawn cuttings is a very effective mulch. You don't need large amounts for your square foot garden beds. About two 5-gallon buckets of cuttings can mulch a standard 4′ x 4′ bed.
You can spread lawn cuttings over your garden when they are either still green or when they are well dried. The cuttings will shrink in size as they dry. Just be sure to not pile green grass cuttings too deeply (not more than 2″ or so), otherwise it can start rotting very quickly, forming a stinky, slimy mess. Lawn cuttings piled too thick, either green or dry, can also start to form a very dense mat than can repel water and reduce air penetration. Thick piles can also become very moldy, which can cause problems for people with allergies.
The easiest way to collect lawn cuttings is by using a collecting bag with your mower. Be sure to empty it often as you mow. If the bag fills up, it will start leaving cuttings on the lawn instead of collecting more. When I used to rake grass cuttings by hand, I would usually let the grass grow taller than normal before mowing, so that the cuttings were thicker and easier to rake. I realize that this is counter to the formal recommendations to only cut 1/3 of the grass leaf length at each mowing, but my grass seemed to thrive despite my occasionally breaking this mowing “rule”.
In autumn, lawn cuttings often have a mixture of green grass and brown leaves, which make a lovely winter mulch for your garden beds.
Do NOT collect cuttings from lawns that are treated with pesticides or herbicides. Some of these chemicals can damage the plants growing in your garden for months after you have spread the contaminated mulch.
There are only a couple of times during the year that I do not have a 1-2″ layer of mulch on my vegetable beds:
1) In very early spring, I may remove the mulch for a couple of weeks, to allow the soil to warm up and dry out faster. This is especially important when I will be planting warm season vegetables, such as tomatoes or squash. If you garden where summers are very cool, a mulch may slow the growth of your plants too much, and you might only apply mulch in late summer or during the winter.
2) When I plant small seeds (such as carrots or lettuce), I usually only sprinkle a very thin layer of mulch on the garden bed – so I will see perhaps 50% bare soil and 50% mulch.
This allows the seeds to germinate easily, but the thin layer of mulch helps prevent the soil from drying out too fast while the seeds are sprouting – especially during hot summer weather. As soon as the plants are big enough, I'll put 1-2″ of mulch between them.
However, in some climates with mild, wet winters – like the U.S. Pacific northwest – a year-round mulch can attract a high population of garden pests, making vegetable gardening extremely difficult. In this situation, you are better off not using year-round mulch. The Pacific northwest also tends to have very cool summers, which is another reason why mulching is not as useful in that climate.
But mulch makes a HUGE difference in my garden and in my climate (hot summers, cold winters). It rapidly improves my soil, and I wouldn’t garden without it!