add leaves to soil in fall?
 

I've noticed around town there are bags of mostly maple and oak leaves curbside, ready to be picked up.

Here's my plan:
1. shred bags of leaves with mower
2. add the shredded leaves to greenhouse raised beds
3. till the leaves into the soil
4. cover the raised beds with black plastic

Would that help to improve my heavy clay soils?

This is all inside a hoop house that will be covered with 2 layers of poly over the winter. I'm thinking the black plastic will help to heat up the ground, thereby speeding up the compost process. On a sunny day, even with outdoor temps of 20-30 deg. F, inside the greenhouse can be 90.

Thoughts?

Yes.

I have not used the black plastic nor grown inside a hoop house, but oak leaves shredded and tilled in does improve the soil. We till our gardens a few days ago that have been amended with shredded oak leaves for the past 5 years. The soil smells like worm heaven :) My brother picked up a handful of soil, smelled it, and said, "People would pay good money for this soil!" Anywhere else on our 10 acres - the soil smells either like dust or heavy clay.

My answer is YES it helps.

My thoughts: I would use the leaves as "browns" [carbon] in a compost mixed with "greens" [nitrogen] , and let it finish decomposing first. To compost you need both. Otherwise the process of only leaves in your soil decomposing would take a long time, and greatly reduce the nitrogen available to your plants. (I don't think heat would help very much.)

Steve

I do collect bags of leaves from the curbside and add them to my beds each year. I cover them with soil so the leaves do not blow away. I also add some Mycogro. Yes, there are some leaves that have not broken all the way down by planting time, but it has not caused any problems for me. I even will add more to my planting holes when I plant out my tomatoes. Of course I will throw in some fertilizer when I plant out. My plants still get plenty tall and I have not experienced a lack of nitrogen doing this. My clay soil has improved dramatically, the texture is great. I also now have an abundance of worms and fungi in the soil. Go ahead and give it a try.....

I don't think you can add too many leaves to amend native soils. They will break down even without a green component as long as they're mixed into the soil.
I add many trailer loads of leaves and horse manure to my gardens every fall. My main source for N comes from cover crops. I think of horse manure as a conditioner, not a fertilizer.
Given the choice between leaves, animal manure or cover crops, I would choose leaves and the more the better.

I also love leaves for tilling into my clay soil but you can overdo it. I did that one year when I collected 85 bags of leaves and tilled them into my 2 in-ground gardens. My peppers had yellow leaves that year due to lack of nitrogen and I had to feed them but by the next year the leaves were totally decomposed and now I have nice dark, fluffy soil. I do keep adding organic matter every year but not usually just leaves, it is a mixture of things including leaves.

Grinding them up with a mower really speeds the decomposition process.

Grinding, shredding, mowing the leaves helps a lot. Using whole leaves can cause them to mat together. I learned this the hard way. Once they become matted together - they get wet, turn black, and stay wet. This happened the first year we added oak leaves. We put the whole leaves on the ground and turned it over/into the soil with a shovel.

A tiller is much easier, and helps shred the leaves even more.

I have heavy Virginia clay soil. I add mower-chopped leaves every fall and like ALittleSalt said . . . it becomes worm heaven!

I just got back the soil test results from VaTech and my previously-horrible-clay was wonderfully balanced.

I also compost as many leaves as I can get in a compost pile and add finished compost throughout the year.

Rome wasn't built in a day and neither is soil.:)
You have to start somewhere.

Worth

I have found the shredded leaves need to be wet to compost in my raised beds. Lasts year was exceptionally dry and the shredded leaves just sat there. Under cover, is there any moisture? Have you considered going year round with growing cold tolerant greens, carrots, etc. Wish I were in your shoes!

I am concerned about using curbside leaves going forward. EAB , the Emerald Ash Borer has migrated to the outlying areas of Omaha, and the tree services can't keep up with the demand to apply pesticides to Ash trees in hopes of keeping the little borers away. Do not need any additional crap in the food I eat. Any way to find out what you are getting?

- Lisa

I do have two leaf compost bins going now and I have read on line that with the right conditions it can take two years for them to break down. We'll see! My husband picks them up with his mower which shreds them and mixes in some amount of grass clippings, so that should help.

What I did last fall is use shredded leaves as a mulch on my raised beds and then left it in place through the growing season. That mulch layer has now completely decomposed, and I will soon be adding a new layer of shredded leaves from one of our final leaf pick up days.

We are cursed/blessed with an over abundance of leaves each fall, so no need to collect bags from the neighbors on the one day per year that our town offers a fee-based curbside leaf pick up. And, using our own, I know what lawn chemicals are/are not mixed in with the leaves

that was my main concern, no moisture in my poly greenhouse to aid in breaking down the leaves.

I currently have 3 rows of lettuce growing; the propane heater only runs at night, during the day I still have to open the sides.
My water supply is about to be shut down though, I have to drain down the sprinklers tomorrow and that will end my water supply.
I put in two 30gal barrels that I plan on filling via a hose from the house. But, I don't want to be wasting my precious 60 gals on watering dirt/leaves.
Fortunately the hose run from house to greenhouse is uphill, so after filling the barrels I can disconnect the hose from house and it will drain out. In a month or so it will be under the snow/ice.

I'm going to be latching down the poly sides soon using wiggle wire, then they will be permanently closed for the winter.

Not sure how long I'm going to keep it running/growing, I guess it depends on how much propane I'm burning and if the heater can keep up. I'll likely shut it down around Christmas, then open it up about March 1st for seedlings and flowers.

I keep unshredded oak leaves in a wire bin for years sometimes, and sometimes I shred them ( in the leaf vacuum). Either way, I use them in the fall as a mulch over garlic and favas in raised beds. I don't use those beds in summer because it is too hot and dry. Seems to me when I go back there to plant favas in the fall, I don't see many recognizable leaves.

If you are interested, Rutgers University cooperative research and extension has a fact sheet titled "Plant Nutrients in Municipal Leaves". I think it shows the C/N ratio is about 45 to 1 on average, so not a lot of extra nitrogen should be needed. I don't have the link but several other sites have copied the info so it should be easy to find.

I'd like to offer a caution. Not all leaves should be used. Walnut, hickory, sweet gum, and a few other types contain "Juglone". This chemical adversely affects or kills many garden veggies, especially the plants of the "Nightshade" family, which includes tomatoes, potatoes, and egg plant.

Having had this chemical destroy my gardens several years ago caused me to grow everything in containers. That's how I chose my handle - ContainerTed.