Am I Using Too Much Compost and Mulch?

In my last couple videos, you saw me carrying dozens of bags of leaves and pale after pale of compost. This prompted a few of you to wonder if I might be adding too much organic matter to the garden, and ,in retrospect, I can see how these images might have given that impression. So, today I thought I’d talk about how much mulch and compost we add to the garden, and begin to address the question “is it too much?” Let’s start with compost. We added more compost this year than ever before, and based on the dimensions of our five compost bins, I can provide a fairly accurate estimate of how much. Our largest bin provided about 1 cubic yard of compost. We emptied all 0.9 cubic yards from this bin. This temporary bin yielded about 0.7 cubic yards. 0.5 cubic yards were harvested from this bin. And, finally, though this bin holds 1.25 cubic yards, we only harvested, at most, a quarter of that, or about 0.3 cubic yards. That gives us a total of 3.4 cubic yards of compost. But wait a minute. We added quite a bit of vermicompost to the garden too, so let’s make sure to add that to the total. Here more guesswork is involved because we usually harvest castings a little at a time, as they’re needed, which makes the quantity harder to gauge. My best guess, though, is that we added about 0.33 cubic yards of vermicompost to the garden this year, bringing our total to 3.73 cubic yards. Now let’s use a landscape calculator to figure out how much compost we’d need to add 2 inches of compost to our 580 square feet of growing space. I chose 2 inches based on horticulturist Jeff Gillman’s recommendation to amend garden beds with 2 to 3 inches of compost per year. I enter a length and width that will give the desired 580 square feet; and enter a depth of 2 inches. It turns out we’d need 3.6 cubic yards to add 2 inches of compost. So, the 3.73 cubic yards we harvested was just enough! If we wanted to add 3 inches, we’d need 5.4 cubic yards. As I mentioned earlier, we added more compost this year than ever before. For example, in prior years we didn’t harvest compost from this compost bin. So, subtracting the one cubic yard of compost it produced, leaves us with 1 ½ inches of compost. And two years ago, we also didn’t harvest from this bin. Subtracting the 0.5 cubic yards it provided leaves us with only 1 1/4 inches of compost applied to the garden. So, at least by the standard of 2 to 3 inches per year, we’re not applying too much compost to the garden. In fact, most years we apply considerably less than 2 inches. Now let’s talk mulch. As with compost, Gillman recommends adding as much as 2 to 3 inches of mulch per year to perennial and no-till garden beds. While it was pretty straight forward estimating how much compost we use, it’s more difficult to do with mulch. We chop and drop comfrey and garden waste during the spring and summer, and mulch with leaves and used coffee grounds in the fall. We also mulch our blackberries, raspberries, and grapes with wood chips. Last year we mulched our vegetables with aged wood chips as well but didn’t this year because we had a lot of rain and didn’t want the soil to hold too much moisture. Like I said, it’s difficult to estimate, but if I had to guess, I’d say we probably mulch somewhere in the ballpark of 2 to 3 inches per year. So, at least based on Gillman’s recommendations, I don’t think we’re adding too much organic matter to the soil, and I’ve seen no evidence of it in terms of the health of our plants. Even so, I plan to have the soil tested in the spring to get a clearer picture of organic matter and nutrient levels. I’ll pay particular attention to the level of phosphorus, because too much organic matter in the soil can lead to elevated phosphorus levels. So, if the nutrient levels are high, especially the phosphorus, that will be a good indication that we can reduce the amount of compost and mulch that we’re adding to the garden. Well, that’s all for now. Thank you very much for watching, and until next time remember you can change the world one yard at a time.

57 thoughts on “Am I Using Too Much Compost and Mulch?

  1. So my question isn't "too much", but rather what adverse effects would more compost have, if any?  

    "Too much phosphorous"  … should've waited to end to comment.  😉

  2. thank you for this info.  I have been adding well rotted goat manure to the beds each year and have begun using decomposing wood to the tire planters at the base, so each year I have to add more soil as the wood decomposes.  I will be testing my soil as well so I know what I might need to make it better.  I need to plant some leafy trees for more mulch.  Right now I am using date palm fronds stripped from the branches.  They take a long time to decompose though.

  3. I love your scientific approach to gardening! I always just do what feels right…I guess I could eventually get in trouble!(-: Anyway, your garden looks beautiful. Thanks for all the lessons Patrick!

  4. I'm stepping up my game with more compost and mulch too. I just need to walk the neighborhood in search of more leaves.

  5. I know you've discussed using coffee in your garden in other videos, what do you think of combining leaves and coffe grounds where the coffee is the green(nitrogen)?

  6. I got a lot of half ripe compost from the compost factory and stored it in bags and barrels. Now I have a lot of compost worms. Will be good to add to the leaves I guess. 

  7. you can NEVER have to much in my opinon 🙂 You would have to add tons and tons of compost in order to have "too much" 

  8. Great info once again. Thank you for all the knowledge and tips you pass on. You and Steven in Alberta have two of the best gardening channels on YouTube.

  9. If there would be too much P could you balance it with urine (N) and comfrey (K)?
    In addition the abundant bacteria would make bio-available the other minerals from rockdust. Or is it just my theory?

  10. I would suspect that because you're using them in areas under relatively intense cultivation, which is drawing large amounts of nutrients that would need large amounts of organic matter to be replenished, It would be difficult to get to that too much point. Just a thought. Excellent video as always Patrick!

  11. Thank you Patrick.  
    I like how you calculate and give sources for information you share with members. It's a whole lot better than " In my opinion" information. 🙂  I tell you what lol!

    Another well done video.

  12. I have 2 4X4X2 planting boxes and used a truckload of compost to fill them. I used some of the compost on other projects but the plants in the 2 boxes were truly epic. Never grew such hot peppers before

  13. Thanks for the look & information Patrick..
    We get nowhere near 2" of compost onto our beds a year but hope to get to that level soon.. 
    Cheers mate..

  14. Nice analysis. Is there a reason you are waiting until spring to do soil testing? My understanding is that some recommendations, like adding lime, should be done months before planting.

  15. Well done Patrick! I don't think that in small gardens like ours, we'll ever be able to make too much compost, other wise the compost bins would take the whole garden 😉

  16. Great video Patrick. I guess it is pretty hard to overdose on compost unless you have some pretty big piles of compost.

  17. Patrick, Good job.
    Mother Nature never has a limit on compost.
    We take a tomato seed, the size of a broken pencil tip and stick it in the ground and grow a 15' tall plant and harvest pounds of fruit off of it.
    Where did all of the fuel come from?? …..Compost!!!
    If we don't compost, the plants will run out of fuel……. empty gas tank..

  18. Excellent episode Patrick. To be honest this surprised me. I had not thought of the imbalances too much organic material could cause.

    I'd be keen to see the reference material ! The phosphorus levels are of special interest.

    I'm fairly sure I am fine this year as I have not had enough time nor space to make more compost and the only input is mulch.

  19. Great video! Goes to show you that you need to make a TON of compost just to give yourself a couple of inches to add to your garden bed each year. I don't have the capacity to make that much right now but I do think even adding a modest amount can make a measurable difference and attract beneficial microorganisms to the soil.

    Mulch is fantastic. It's so easy to apply. I'm shocked when I see people wasting their leaves by raking them up and putting them in a bag on the curb.

  20. soil is basically compost from branches, leaves, pine needles etc.  so i would say no, you can't use too much mulch or compost.

  21. You would most likely need as much composting space as you have garden space in order to make enough compost to over nutritize ( I know that ain't a word ; )) your gardens! Great vid, Bro!

  22. Nice, I think our best gauge on soil quality is the health of the plants we are growing, like you said

  23. Too much compost would never happen at my place. I know squashes can't get enough tho. Every yeah my best ones grow in the compost pile. Great vid ';)

  24. didn't realize you growing space was so small.  Is this the first time you mention your square foot space?

  25. Sir, well I choose to differ from your point of view. Cause,
    1. there is a lot of diversity on the composted raw material
    2. you have not used any inorganic goods.
    3. naturally no plants or animals will consume more, anything excess will be given back.
    4. when the plants consume they consume all the minerals equally, according to their own needs, so there is no way you can feed them more.
    In case I am wrong I would certainly be grateful for being corrected. Cheers & happy mulching.  

  26. Looks like you've got a pretty good system in place for amending and mulching your grow beds. Great information! And the idea of having your soil tested and adjusting the inputs accordingly is something I'd like to do as well. Thanks for sharing!

  27. Good video. Gotta get a chipper shredder for those mulch clippings, or just run them over with a mower with a mulching blade.

  28. Wow Patrick, I just realized how much compost you produced this year. I measure mine in gallons because I use tots to move compost around my yard.. I totaled up my compost volume for the year, and I produced 200+ gallons(1 cubic yard).,,, and I thought I made a lot. You produced 3-4 times more! Regardless if it is "too much compost" you should feel good about recycling that much yard waste and materials. Good Job!

  29. You mentioned that your chop and drop the comfrey in spring and summer but aren't you using those same beds to grow food in that you dropped the comfrey in?  If so, how does that all work in terms of; are you turning the soil over on top of the comfrey so that you can plant in the beds while the comfrey is being broken down at the bottom of the bed, or are you not planting in those beds until the comfrey is broken down?

  30. I'm a complete novice at gardening, with this being my first year, so this is probably a dumb question, but here it is anyway:  Isn't compost essentially just rich soil, much like topsoil you can buy?  And if so, how can you use too much?  Couldn't you grow your veggies in 100% compost, and wouldn't that be ideal? Or are you just worried that you're wasting it by using more than necessary, but not adversely affecting the conditions? (My garden is pretty small for now, so that wouldn't be an issue for me.)

  31. Too much compost? That's like too much top soil – I don't think there is such a thing really. I inherited poor soil (broken record) and have been enriching the soil with compost, vermicompost, green manures, manures, and mulch for 30+ YEARS and see no signs of anything other than better soil.

  32. for the phosphorus try to get bone flour. aply 5 months before planting your beds and it will release phosphorus slowly to your plant

  33. ENJOYS YOUR VIDEOS. SO IF THERE IS TO MUCH PHOSPHOROUS. WHAT DO YOU INCORPORATE TO AMEND THE PROBLEM ? I like the formula break down you show for the space needed. I saw on one of the comments to add more bone meal. Mr. Steve Soloman author, has many years of a methoud using natural organic seed meals, Minerals, Rock dust, kelp, Bone meal. Sea weed, or Fish meal. Gypsom or Ag lime, Dolometic lime in his gardens ETC: He has the most terrific gardens year after year. Think anyone interested could You Tube him. That would be good to go along with your methods of making compost:

  34. With all due respect I come from a generation of old school farmers, who knew nothing of all these techniques. My parents grew up with wood wagons, iron wheels and mules. My Daddy's side was Mennonite from Ukraine, whose people brought a prosperous winter wheat to place Kansas on the map as the bread basket of the Americas along with improved farming equipment. My mama was still-born in a dirt floor cabin built with axes by my grandfather and his brother in 1916 in the NW Smokies of North Carolina.. He assisted, brought her around and somehow in the back woods they managed. There is so much confusing info . I like your stuff. Pleae carry on. "Stay poor. Stay Hungry." – Earthbook 1968. My oldest uncle was born in a sod hut on the Kansas plain where buffalo chips were burned for fuel. And life goes on… Thanks again.

  35. Enjoying your videos. The rock dust question has puzzled me as I believe that much of it is sourced from gravel pits. Crushing to size rock for gravel produces a fine powder at the base of the sorting screens..I have tried to get access to this at a local gravel pit but told it was not available as someone else had secured it with management.

  36. If you add a couple inches of compost and mulch each year, then are you putting new compost on top of last years mulch? Doesn't that lock up nitrogen? I always wonder how to use a lot of mulch, and then plant crops, especially direct seeding greens and such, and add compost without moving mulch underneath. Thanks

  37. Every time I learn something important. I (and my family) are eating more good food from our garden because in large part of the education you pass on here.

  38. the best garden i ever had was all compost in a raise 6 inch lasagna raised bed, the compost was leaves and grass dumped in the same spot for over 20 years. more tomatoes , potatoes, peppers and beans than ever

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