So, your compost pile is ready and you want to know how to use compost in your organic garden. Here are 4 things to remember:
1. Compost Application Timing
The best time of year for using compost is in the spring and fall when the conditions are best for the microbes. I might use a little in the summer when I'm filling in the spaces in my vegetable garden, but mostly it's spring and fall.
In the spring, I apply compost at least two weeks before planting to give some time for it to get acquainted with the soil.
You can use compost in the fall, but if you live in an area of high rainfall, you may want to cover your compost pile for the winter and wait until the spring to apply it, in order to avoid leaching some of the valuable nutrients.
2. How To Use Compost For New Garden Beds
If I’m using compost to make a new garden bed or installing a new lawn in a soil without much organic matter, I’ll often till 2-6 inches of compost into the top 8-10 inches of soil. That’s generally too much compost to use more than once in the same garden, but for a soil that is low in organic matter, it’s useful to get that in there in the beginning.
I don't do a lot of tilling in my organic garden, but if I'm putting in a new bed, I may till or double dig in a whole whack of compost to get the organic matter down deep.
I know this hurts my soil structure and many of the microbes and small animals living in it, but this will be fixed after a few years and the organic matter will be there for much longer. I don't want to do this damage every year, though.
3. How To Use Compost For Maintenance
For maintenance on existing beds, I’ll apply between 1/8 inch and 1/4 inch to the surface. I may lightly incorporate it, but I don’t do much tilling for maintenance. For an existing lawn, you can screen out sticks and big clumps and apply it at 1/4 inch thick. If possible, do this annually.
As I said, for maintaining nutrients and microbes, 2-3 inches is much more than needed. The Luebke’s in Austria recommend 10-12 tons per acre to start and then down to 3-8 tons for maintenance. Elaine Ingham recommends a maximum of 10 tons per acre and more like 1-5 tons per acre for maintenance.
By my math, 12 tons per acre is only about 2/5 yard of compost (1/8 inch thick) per 1000 square feet and 1 ton per acre is only about 7 gallons of compost (1/90 inch thick) per 1000 square feet.
Many gardeners and farmers apply too much compost, which results in nutrient imbalances, nutrient leaching and subsequent pollution of our waterways, and volatization into the atmosphere as greenhouse gases.
4. How To Use Compost For Potting Mix
Potting mix is one of my favorite uses for compost. My basic mix consists of 1/3 compost, 1/3 sand and 1/3 soil. I don't want much more compost than this because it may be too rich in nutrients, with not quite enough air if it gets too wet.
So there are 4 things to remember about how to use compost.
- The best of time year is spring and fall
- Till a few inches into a new bed
- Apply less than 1/4 inch on top of the soil each year after that
- Use 1/3 compost in your potting mix
Feel free to ask questions below.