For thriving vegetable gardens with big harvests and healthy soil, it's best to add compost to your garden beds in the fall instead of waiting until spring. Fall is the most important time to improve your soils for the following year.
Should You Add Compost to the Garden in Fall or Spring?
Did you know that the optimal time to add compost to your garden is actually during the fall season?
A common practice among gardeners is to wait until the spring, right before transplanting or direct sowing. While this is not necessarily wrong, it may not be the optimal time.
Compost behaves like a fertilizer, but technically it is not one. The main difference is that compost takes a while to break down, unlike fertilizers. As it decomposes, it slowly and steadily feeds the soil and your plants.
By adding compost during the fall season, your garden beds will have fertile soil the next spring, which can enhance the growth of your plants. The nutrients in the compost will break down and become readily available for the plants to assimilate, leading to more immediate results.
Please note that when I refer to compost here, I'm talking about well-rotted, decomposed, finished compost — or very close to being finished.
How to Add Compost in Fall Garden (Step-by-Step)
The way you add compost to your garden in any season will depend on how you garden.
Our gardening method is no-till, which involves simply adding a 1-inch layer of mature compost (gathered from multiple sources) onto our raised beds in autumn and leaving it undisturbed without any digging or tilling.
There's no need to dig into your soil as it disrupts the millions of helpful microbes, bacteria, mycorrhizal fungi, and other components that maintain the structure and health of your soil.
Digging also brings up weed seeds which will then germinate and sprout in greater numbers the following spring.
The healthiest soil is undisturbed, and tilling is both unnecessary and counterproductive.
But if you don't garden like this — you will likely want to till in your compost into your soil underneath.
With conventional gardening, an inch of compost is the minimum, and up to 4 inches would be ideal.
- Prepare garden beds - Before adding compost, ensure the garden bed is free from weeds or debris. We do not pull up plants by the roots but rather cut them at the soil level and leave the roots to decompose. We also chop-and-drop weeds that have not gone to seed. You may also opt to save the garden clean-up for the late spring as many beneficial pollinators and insects will use your garden debris to overwinter or lay eggs.
- Choose mature compost - Use well-aged, mature compost or compost that is nearly finished. This type of compost is rich in nutrients and beneficial microorganisms, providing optimal benefits for your garden.
- Apply a layer of compost - Spread a layer of compost evenly over the surface of the garden bed. Aim for a thickness of around 1 to 4 inches (see below for specific recommendations) to provide adequate coverage and nutrient replenishment. See my handy compost calculator to automatically calculate how much you need.
- Avoid disturbing the soil - In a no-till garden, it's important to minimize soil disturbance. Instead of tilling or mixing the compost into the soil, simply leave it on the surface. If you do not use this method, till your compost into your beds and then rake the soil down until it is even.
- Mulch the bed (optional) - After applying the compost, cover the garden bed with a layer of organic mulch. This helps retain moisture, regulate temperature, suppress weed growth, and enhance soil health. Common mulch materials include straw, wood chips, or shredded leaves. I also have a mulch calculator that can help you calculate amounts automatically.
- Let nature do its work - With the compost and mulch in place, let nature take its course. Over time, the compost will naturally interact with the soil, enriching it with nutrients and supporting beneficial microbial activity. The mulch will gradually decompose, contributing to organic matter and maintaining a favorable environment for plant growth.
Compost Amount Recommendations
- No-Till/No-Dig Garden: a 1-inch layer of compost. If establishing brand new beds, 6 inches of compost.
- Conventional Garden: 1-inch minimum, up to 4 inches before tilling into the soil.
- Poor/Compacted Soil: 4 inches. Consider tillage radish and other cover crops, as well as a heavy layer of additional mulch.
Should You Also Add Compost in Spring?
If you added compost in the fall, and your soil is healthy and thriving to begin with, then there is no need to add more compost in the spring.
On the other hand, you can choose to add less.
During spring, you can opt to add compost only to the planting holes where you will be transplanting, or around the base of your plants once they have been transplanted or have started growing from direct-sown seeds.
This is an alternative to adding compost to the entire garden bed.
That newly added compost will steadily break down and help feed your hungry, heavy feeders like tomatoes and peppers.
For plants like beans and other nitrogen-fixers, I would suggest this is unnecessary.
How Much Compost Do I Add In The Fall?
You do not need to add more than an inch of compost in the fall (or spring) to your garden beds. If you rototill your beds, you should try to add more, up to 4 inches of compost.
Another exception would be if you were starting new no-till/no-dig beds. In that case, you will want to add 6 inches of compost.
Some gardeners only add a ½ inch, but they have very healthy soils and very well-established garden beds.
The Best Compost
The best compost is the one you make — ideally from multiple sources.
For example, we have high-nitrogen chicken litter compost we collect each year when we clean out the coops from our deep litter method.
That compost is left to mature for a whole year after the fact.
Then we have the straw and discarded hay and sheep manure from our Icelandic sheep, who spend the entire winter inside their sheep shed.
We also have kitchen compost full of scraps from the kitchen, along with weeds, cardboard and paper, leaves, grass clippings, and other materials.
And we also have access to mushroom compost from a farm.
When To Add Compost To Perennial Garden
When adding compost to a perennial bed, it is best to do so during the fall season. It is recommended to apply a layer that is one inch thick, and there is no need to add more during the spring.
Do You Add Compost Before Or After Planting?
Before planting, it is best to add compost to the soil. This allows soil microbes to break it down, making it more accessible to plants. If you plan on growing heavy feeders like tomatoes and peppers, it is recommended to add extra compost into the planting holes for optimal growth.
You can also use compost as mulch on your entire garden bed, or just around the base of plants.
In a no-till bed, you should add 1 inch of compost.
In a conventional garden bed, add up to 4 inches and till it into your soil.
Do You Put Compost On Top Of Soil?
The best practice is to put a layer of compost on top of the soil. Not only will that layer act as a mulch to protect your soil, but the compost will also feed your soil and, thus, your plants.
Conventional gardeners will till compost into the soil, and although this may be beneficial in specific circumstances, there is no need to do so. If you insist on tilling, try to add up to 4 inches of compost.
Is It Too Late To Add Compost To a Garden?
There is a possibility that it could be too late if you plan on adding compost onto poor soil or mixing it into poor soil and then immediately planting afterward.
It is still recommended to add compost to your plants, however, it is important to note that they may require additional fertilizers or a larger amount of fertilizer as they begin to grow.
Should I Add Compost To the Garden Before Winter?
Fall is the ideal time to add compost to your garden before winter arrives. This is the perfect opportunity to enhance your soil and prepare your beds for the colder weather and upcoming growing season.
Do You Put Compost Before Or After Soil?
The best planting medium for a vegetable garden is straight-up compost from various sources. The second best is soil with as much compost as possible mixed into it — at least 30%.
It is a myth that you can't or shouldn't plant directly into compost; there is nothing about that bit of gardening advice that is remotely true, as countless experts have demonstrated successfully.
See my article on soil vs compost for more of an explanation.
When first building or establishing your raised beds or garden beds, the compost should be mixed in and combined with your soil and whatever other organic matters you're using.
Afterward, there is no need to till or dig the compost, it can simply be layered on. The less digging and soil disturbance, the less compost you need.
When deciding to add compost to garden in fall or spring, consider that the fall is a crucial time to improve your soil and get it ready for the following growing year.
Adding compost to your garden in the fall offers numerous benefits that make it a preferable choice over spring application. By incorporating compost in the autumn, you provide ample time to break down and integrate with the soil, maximizing its nutrient content and improving soil structure.
Fall composting also helps to replenish depleted nutrients after the growing season, ensuring that your plants receive the essential elements they need for robust growth in the following year.
The cooler temperatures and increased moisture in fall create favorable conditions for microbial activity and decomposition, facilitating the transformation of compost into rich, fertile soil. Embracing the practice of fall composting sets the stage for a thriving garden, healthier plants, and sustainable gardening practices.