How To Use Compost – 4 Important Things To Remember
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.
not to confuse compost with mulch, right? because significantly more mulch should be applied?
You’re right, I try to keep a 2-4 inch mulch layer at all times.
Thanks for doing the math on the tons per acre.
thank you for providing a perfect timing for compost application. artificial hedges is good way to decorate you home .
Thanks for potting mix recipe. Is this for seeds too?
Yes, I use it for seeds, but you have to be careful to screen out organic debris and not use too much sand. When filming the ‘starting seeds’ section of the academy, I did a poor job of this, so my seeds didn’t do as well as they should have.
Would you advice to use vermiculite and perlite in the potting mix for container gardening? Thanks!
I have just mixed organic compost purchased from a garden supplier into some red clay type soil, I dug into the top 8 inches and then placed about 3 inches of compost on top and tilled it in several times. I have planted seedlings and was about to plant more but on turning the top couple of inches of soil have found that beneath that is a blue/grey powdery substance can you tell me what it may be and if it is going to damage my seedlings, the soil is now well drained after using the compost.
My guess would be that it’s a lack of air. The clay makes for that. Are you getting a lot of rain these days? That contributes to it, too. To improve drainage, you need to 1) increase organic matter as you’re doing 2) get a soil test from a good organic lab and balance out the nutrient ratios, because that will actually improve drainage tremendously.
I am starting a planter salsa garden box, I have never done any kind of gardening. I have Fox Farms potting soil, Organic Buffalo Compost, and Happy Tree Frog fertilizer. Should I mix in some compost with my soil and let it sit for a week or so before planting? Just need some help starting it up, thank you!
Yes, exactly Emily. Just mix in approximately 1/3 compost and 2/3 soil along with some fertilizer, and then it’s a great idea to wait a week before planting.
Hi, I have a long driveway and I’m planning to use the back half for a yard, about 17′ x 38′ is what it will be. Right now there is only about a 10″ depth of rocks (very tiny and small, also some medium sized ones) with sand below it. I am thinking about using free compost (from a berry farm near by) and maybe throwing in a few bags of composted cow manure and some peat moss to thin up the mixture. Money is an issue, as I will need to put up a fence, etc. Do you think this mixture will work ? I do hope to grow grass and plants in the future…. I live in the northeast, if that makes any difference. Could use some input, what do you think? Thanx….
The manure and peat moss are unnecessary and even counter-productive. Compost – if it’s good compost – beats them both. You’ll obviously want to remove the rocks if you want an optimally health lawn and plants.
Thanks Phil for the reply. I have spoken with the owners of the farm and they said the compost pile is made up of multiple people’s yard waste and some landscapers use it too. They said it’s mainly leaves, sticks, branches, etc., It does appear to be pretty good (even has multiple bugs but no worms yet). You still don’t think I need manure, right ? Thanks again, I’ve never built a yard from scratch with freebies before….but it is sort-of fun ! Let me know on the manure please..
Correct, no need for (or benefit from) manure. Compost does basically everything manure does and more.
Hi Phil. Would cow manure be a suitable substitute to compost for soil maintenance? If yes, should I follow the same application instruction you highlighted above for soil maintenance? Thx!
For the most part, you don’t want to put manure directly where there are plants because it can burn them, but with cow manure, a thin layer should be okay with regards to this, and if you’re preparing soil where there won’t be any plants for at least a month, it’s less of an issue. The remaining problem with many manures, including cow manure, is that they can contain a lot of weed seeds, which means you’re sowing your soil with weeds. It depends on the cow’s diet, but this can be an issue. For both of these reasons (burning and weed seeds), it’s ideal to first hot compost any manure (and of course, composting brings many other benefits as well).
Hi Phil,
I started composting in Fall, and it’s the beginning of May and my compost still does not look ready. Can I use it as a mulch on my garden beds and wait for 3-4 weeks before transplanting? This is my first year in home gardening and any help would be appreciated.
Thanks,
richa
If there are food scraps in there, you probably wouldn’t want to spread them out as mulch because they’ll attract rodents. Also, if there are many weed seeds in it, you probably don’t want to spread it. But if it’s just manure and plant debris, yes, you could use it as a mulch instead, on top of the soil. And you don’t have to wait to transplant in that case.
I have a 150 sq ft raised bed, and it’s only my 2nd year gardening. Got a great yield my 1st year, but didn’t know to amend and mulch the beds for the northern NJ winter/snow. Now 1.5 months before planting, my soil looks devoid of nutrients/organic matter. It’s light brown/grey, and not like crumbled chocolate cake (I watch too many gardening videos). What’s the best way to amend the soil to give me a good season? Do I till? Add compost? Work casings? Azomite rock dust? Every garden website has different recommendations and I don’t know where to start!
Your soil doesn’t necessarily have to look like crumbled chocolate cake. Indeed, soils that do may actually have too much compost in them. But to answer your questions, your soil will probably benefit from adding a little of any/all of those things – compost or worm castings plus Azomite or another rock dust. As for tilling, I try not to do too much of that because although it makes the soil look nice, it’s not necessarily good for it: https://www.smilinggardener.com/lessons/garden-tilling-soil/
I live on the NJ coast and have not been successful in establishing a lawn. The ground is hard as a rock during warm sunny days and does not drain well; compacted. I have had several large oaks on the property removed but the roots remain. This year, I decided to put in wildflowers native to NJ. Should I amend/enhance the soil by tilling in some compost before I plant the seeds?
Yes, if you can find good compost, that would be a good step.
Thanks. Good compost is hard to come by here on the east coast (NJ) . The stuff I had delivered in bulk last time was full of trash, sticks and rocks not to mention tons of weed seeds. The bagged compost is pricey and I have a large area to do. Guess I could scale way back and just do one small section per year. Thanks
I think I already messed up. I filled a large raised bed with about 50% yard dirt and 50% bulk compost from my local plant nursery.
Now I realize (belatedly) I probably put in too much compost. What should I do now? The beds are totally full- no room for more soil.
I see 2 main options: 1) You can plant in that as it is, and some things – perhaps many things – will be okay with that much compost. And in subsequent years, as the compost breaks down, the soil should get better and better. 2) You can remove 50% of the mix and save it for the future (another raised bed, containers, etc) and then fill up the bed with more yard dirt so you’re down to 25% compost in the bed. I suppose a third option would be to start with #1 and if it doesn’t work out this spring, do #2 this summer and plant for a fall garden.