Compost is a valuable resource and composting is a valuable practice to family households, small- and large-scale agriculture sites, and larger institutions. Whether you maintain your own compost pile or use a service, composting helps divert organic waste from landfills, curbing greenhouse gas emissions while creating a soil-building amendment that improves soil quality, soil health, and soil structure over time of a variety of soil types. Not only does composting improve soil, but the process recycles and puts to use a constant stream of waste that would otherwise be trashed (literally!). If you’re composting, you’ve definitely got plentiful compost on your hands a few times a year, but how and where should you use it? There are numerous ways, like preparing and maintaining garden beds, mulching, making potting mixes, and seed starters, helping your lawn become greener (color AND eco-friendlier), and transplanting in new landscape elements. Let’s dig in to the eight ways to use compost at home!
1. Preparing Garden Beds
Gardens are the first places that spring to mind when you’re thinking of compost application. Compost applied to garden soils helps to rebuild older soils, replenishes organic matter, increases the nutrient retention abilities of your soil, adds some slow-release nutrients, helps to bolster the microbial community in the soil, and helps your soil retain water to help cut down the water bill while assisting water in filtering through the soil profile, rather than pooling at the top.
When beginning a garden, the prep work starts earlier than you may think! Design and prepare your garden bed area the season before you intend to grow in it. To prepare soil for future plantings, simply add a layer of compost a few inches (2-4 inches) thick and gently work it into the top couple inches of soil with a pitchfork or shovel. Repeat each season before the season you’re planting for (if prepping for spring, prepare in fall) until soil is dark and crumbly. Bonus points if you find ample earthworms and other beneficial soil organisms that point to healthy soil!
2. Producing Gardens
If you’re applying compost for a producing garden area, apply several inches of compost in the fall after you’ve removed the spent summer annuals, just like you would in a newly-implemented garden. Mix the compost into the top couple inches of soil and allow it to integrate over winter. When spring rolls in and the more intensive planting begins, more compost can be added at the time of transplanting or seeding and throughout the growing season in a practice called ‘side dressing’. To side dress your garden, wait until seedlings are established or plants are producing fruit or actively flowering and simply scatter a few handfuls of compost around your plants or apply about 1 inch of compost between the rows of in your garden. With the small amount of compost used in side dressing, soil organisms like beetles and earthworms will do a lot of the heavy-lifting for you. Their normal activities will integrate the compost into the soil profile, but it’s also fine to poke a few holes around to fill with compost.
When planting your garden, add a handful of compost to each hole before adding a seedling. If you’re direct seeding, skip the holes and add another layer of compost before planting seeds. Compost will work to nourish the seeds and seedlings as they sprout and grow into colorful, tasty veggies!
Skip the bagged mulch: spread a layer of compost on top of a finished garden as a mulch to prevent weeds all season long! Compost added to the top of soil as a mulch increases the soil moisture, aides in moisture retention, and shades out weed seeds like a traditional chipped wood mulch, but comes from a sustainable, renewable source that adds organic matter to the soil. Compost mulch breaks down much quicker than a wooden mulch, which is wonderful for the soil. A compost mulch also skips the nasty synthetic dyes present in most store-bought mulch. These dyes added to give the mulch a consistent color leach the coloring agents into the soil, destroying soil microbial populations that are integral for sustained plant and soil health.
Just like wooden mulches, it’s important to keep mulch applications at least 3-5 inches away from the stems of plants and trunks of young trees and shrubs, and at least 8-10 inches away from the base of mature trees and shrubs. Placing mulch too close to the stems or trunks of plants can result in disease transmission. While compost does help to inhibit soil-borne diseases, it’s easier to be safe than sorry, especially around established growth.
4. Amending Poor Soil
While this use could fall under “preparing garden beds,” not all soil that’s in need of some building up is destined to support flowers and veggies. Poor soil can be present around homes due to new construction, hardscaping, or even just soil type in the area. Whatever the cause, poor soils generally have issues with hosting plant and organismal life, leaving them susceptible to things like wind and rain erosion, surface runoff, and loss of organic matter due to direct exposure to sunlight and extreme temperatures. Picture that barren, scrabbly spot on your lawn that just will not grow grass or cover of any kind, no matter how many seeds you scatter around! Compost can and should be applied to spaces like this. Use a pitchfork or a small auger and poke or drill shallow holes a few inches deep into this soil. Fill them with compost and watch the soil remediate! While not instant, the organic matter in the compost will have an easier time incorporating into the soil with more surface contact. Repeat the compost application in this method every few weeks or until soil begins to be dark and crumbly. Add seed or seedlings when seasonally appropriate and enjoy what was formerly a baren spot.
5. Turf and Grass Maintenance
While huge, green lawns are dropping in popularity as the evidence that a biodiverse yard area is best for the environment, many families are still opting to host some grassy spaces for outdoor play spaces. While it’s important to have some pollinator hosting areas, a healthy lawn can be achieved without destroying your lawns micro-ecosystem.
Since lawns and grasses are most often purely vegetative and don’t flower, nitrogen is needed to keep the grass green and growing. Typically, a synthetic nitrogen fertilizer is applied, but if the soil beneath the grass isn’t able to hold onto the nitrogen, it heads straight down through the soil and into the water supply. The EPA has found that 40-60% of lawn-applied fertilizer doesn’t make it into plants. Luckily, compost exists! Finely screened compost (use a ¼ inch sieve if using your own home-made compost) can be raked over lawns to provide nutrients and improve soil structure. Compost application to lawns can cut down on bald spots by conditioning the soil to be healthier and supporting the growth of new grass seed while replacing most of the need for synthetic fertilizers! Compost acts as a low-content slow-release fertilizer, as the organic nutrients convert over to inorganic versions able to be taken up by plants, plants have more time to take up nutrients when they need them. Due to compost’s unique ability to increase a soil’s nutrient holding capacity, less nutrients are lost to runoff and leaching. That’s a win for you, your lawn, and the environment!
Another thing to help with hosting a luscious lawn space is mowing height. Set your mower blades to three inches in height to keep enough green tops on your grass to allow them to set down a strong root system. This is particularly important for newly laid turf and sod. Adding compost to lawn spaces allows for great water infiltration, better nutrient retention, and a longer-term supply of nutrients available for your grass to take up.
6. Seedling Starter
There are plants that hate to be moved and have their roots messed with and then there are some plants just grow better when they’re transplanted as seedlings. Tomatoes, eggplant, peppers, celery, onions, leeks, kale, broccoli, kohlrabi, and collards all grow best when transplanted into your garden rather than starting from a directly-sowed seed.
For a great seedling starter mix, combine two parts compost, two parts coconut coir, and one part perlite to get seedlings started in a healthy, well-draining environment! Measurements are in volume, so as long as the ratio remains 2:2:1, you can use whichever units you please. Opt for coconut coir over peat, as coconut coir is a renewable resource, while peat must be farmed from bogs. Bogs need their peat to act as a carbon sink, so the less we can disturb them, the better!
When your seedlings are nearing their planting date, begin to harden them off before transplanting. The process of slowly exposing the seedlings to outdoor conditions will lessen the amount of shock the transplants experience when planted and will result in healthier plants.
7. Transplanting Flowers, Bushes, and Saplings
As we all know by now, compost is great for the garden! It’s great to prep the garden and supplement the garden soil as the growing season continues. It’s also great to assist with all your landscaping needs! For anything large that’s transplanting into a new home, add a handful (or a few) of compost into the hole before placing the plant into its new space. Be sure to thoroughly water the new transplant in to help it acclimate to its new home and avoid severe transplant shock. For any new transplants, add a mulching layer of compost 5-10 inches away from the base of the plant.
8. Houseplant Potting Mixes & Outdoor Potted Plants
Yep, compost is great for all your in-the-soil needs, but what about the window boxes, potted plants, and houseplants? Let them join in the compost fun, too! Compost is a great amendment to a potting mix to slowly nourish plants in containers. Add a handful to small (6 inch or less) pots and up to a quarter or half of the volume for larger pots. Just like the seedling mix, compost can be used to make your own potting mix. While the ratio for seedlings was 2:2:1 compost, coconut coir, and perlite, potting mix can be created following a 1:1:1 ratio of the same ingredients. If your plants prefer a little more moisture, do a mix of 1:1:1:1 compost, coconut coir, perlite, and topsoil. As before, these ratios are for a volume of mix and can be used to make as much or as little mix as is needed! As your plants bloom and grow, a handful of compost can be added once or twice a year to keep them going and growing.