Megan

Last year I started using shredded leaves as mulch, and also tilling into the soil.( My soil is mostly clay and hadr pan. I add a little 34-0-0 along to give a little nitrogen.

My soil test came back as P 363 ppm (above optimum) on the end that had the least amount of leeves tilled in. The K was 560 ppm ( above optium). Zn was 32.0 ( above optimum)
the PH was 6.2 on this end of the garden.

The orher end was added last year and had the most leaves tilled into it. the P 515, k 958, Zn 52.5 PH 6.5.

Comment on the test said to add 3 lb of 34-0-0 at planting time per 1000 sq ft. All of the garden looks good.

Larry

Megan,

I like Larry's advice.

Theoretically, bark mulch on the surface of the soil will not tie up much nitrogen...only right at the soil surface where it makes direct contact with the soil. However, since you're using so much mulch, I think it wouldn't hurt to add the nitrogen product of your choice.

Whether to add nitrogen or not is a choice only you can make. I am sure you're aware of the issues caused by too much nitrogen....all leaves and poor fruitset. It all depends though on what you're trying to do. Adding nitrogen will enable the mulch to break down much more quickly, so if you'd prefer for your mulch to remain intact as long as possible, add nitrogen to the soil before you plant and don't add it to the mulch. If you want your mulch to break down as quickly as possible so you can rototill it into the soil before planting next year, add the nitrogen to the mulch layer as well.

Nothing has improved my soil as much as regular additions of organic material. I mulch heavily every year, using everything I can get my hands on....cardboard, paper, bark mulch, grass clippings, straw, hay, even weeds I've pulled up out of the ground. (Weeds are great mineral accumulators so if you let them lay there in the mulch and decompose, you're putting those minerals right back into your growing beds.) I don't add extra nitrogen to the mulch because the non-woody portions of my mulch provide nitrogen as they break down....but my beds are in the 10th, 11th or 12th year depending on which bed we're talking about. If you're trying to fast-track the improvement of your garden area, I'd use the compost and leaves on the soil surface around the plants and the bark on top of all that and I'd add a little nitrogen, but not too much.

Don't forget, you can always come back and add nitrogen at any point during the growing season if your plants seem nitrogen deprived. However, if you add too much, you can not remove it. With nitrogen, it is better to slightly underdo it than to overdo it.

Most of my beds have either compost or chopped/shredded leaves as the intial mulch layer. On top of that they have a combination of things, including cardboard, chopped/shredded leaves, wood mulch, freshly pulled weeds (always pull before they go to seed) and grass clippings. I add grass clippings to one bed or another every time I mow and have found that the clippings alone provide all the nitrogen my garden needs.

Dawn

Megan,
My garden is a classic example of one that is high to extremely high in N-P and K. I have only added mulch and manure for the last several years. And no manure at all this year due to the high readings. The above suggestions I agree with. From my experience if it was me here in my semi arid area I wouldn't add anything to the mulch now as long as you leave it on the surface. After you remove the crops I would till it in and add some N then. I've used loose hay mainly alfalfa, straw, lots of grass clippings and leaves the last several years. Any mulch left on the surface like Dawn said will have very little effect on the soil below from my experience. If tilled in then it ties up N. I've used old hay before and have never had much weed problems if I applied it real heavy. But prefer loose or old alfalfa. And I usually have plenty from around the hay stacks.

Like Dawn stated I've learned to be very careful using N. And 34-0-0 sounds high to me. Not sure what kind you are using. You can easily have the most beautiful garden in your area with very few vegetables. I've seen it several times. When I used a fertilizer for tomatoes early in the season I wanted the middle number real high and the N on the low side. Again each of us has different soils and what works is a little different for each. Jay

Thanks for the advice!

Most of the places I looked people seemed adamant that you SHOULD NOT use wood mulch in a veggie garden. So, I looked it up on this forum and saw that Dawn had mentioned using pine in another post and some others had said they had used it, so I figured maybe it wasn't as big of a deal as some seem to make it out to be.

I think that I will use the wood mulch everywhere except for right around the plants, where I will use my leaves. I'll try to keep it all on the surface and just feed the plants for now. We'll be adding a lot of our own (less hot) compost and maybe some worm castings later on. I'm also thinking that I may put a layer of chopped hay under the wood mulch. Maybe the wood will suppress any seeds and the hay can help out our pathetic soil.

These are first and second year beds--and it definitely shows. It goes from pure sinking sand to the hardest clay in a couple of steps with nothing in between. The soil test this year said that it was pretty low in N, P & K, so I mixed up a version of Steve Solomon's organic fertilizer recipe and added it to the soil when we tilled. We also added a thin layer of compost as we were digging the mounded beds. That's why I was a little leery of adding too much nitrogen to the already fertilized beds. I definitely don't want a field of luscious tomato plants that refuse to set fruit! I would like for the mulch to break down quickly, so I may add some more nitrogen towards the end of the season or when we plant a cover crop.

The other thing that the soil test said was that the soil was too acidic. I added lime, but did it more sparingly than it suggested. Do you think that'll be a problem with the wood when we till it in?

I've never had these problems before because our last big garden was at a country house that was built in the 40s. The soil was nice and dark and loamy. This is a newer neighborhood that was mostly developed about 20 years ago, so there isn't a lot of good topsoil.

-Megan

Great thread and timely. I am doing lasagna gardening with cardboard and free fir bark...the bark has been sitting for a few months and has been breaking down already but I appreciate hearing how people are using extra nitrogen sources to break it down further. My soil is basically pretty inert so we are putting in a lasagna layer this year and hopefully can plant next year after it sets for awhile. I guess I am confused about getting too high readings if the soil is already low in NPK and you add in one year...wouldn't things settle in? My veggies for now are in raised beds and I am only planting berries and ornamentals where the cardboard and mulch is going. Thoughts?

Here is a link that might be useful: Organic Garden Club

Megan,

I think there must be a difference in how wood bark mulch performs in a hot, dry climate versus a cooler, more moist one. Here's how/why I decided to try bark mulch.

We have very dense and hard red clay soil. Just picture the Red River's banks, and that's what we have. During our frequent periods of drought, it dries as hard as concrete and cracks. At times like that, it doesn't absorb water....the water runs right off just like it runs off concrete pavement. Once the soil is that dry, I can water 24/7 and the water doesn't get absorbed into the clay...it just runs downhill.

I noticed that our woodland areas didn't have that problem and that the woodland plants tolerated drought much better than the prairie plants and the struggling plants in our young flower beds and veggie garden So, when building our veggie and flower beds, I decided to emulate the soil found in a woodland.

If you walked into our woodland today, a mere 15 feet from the edge of the veggie garden, what would you find? On the surface, you'd find nearly intact fallen leaves, plant debris from understory plants, and small twigs or limbs on the surface. You might find bits of bark shed by trees, or even whole trees that have died and fallen and lay rotting on the forest floor. If you dig down beneath the uppermost layer, you find several inches of similar materials but in a more decomposed state...somewhere between being slightly decomposed to being completely compost. Go down far enough...maybe 8 to 12", and you find the same hideous red clay soil that plagues us almost all over the property. In the woodland, though, soil is literally building itself through the natural breakdown and decompostion of natural materials. If having all that bark (including entire dead trees) lying on the soil surface is hurting our woodland, you sure cannot tell by looking at it. So, after struggling to improve clay by rototilling copious amounts of organic matter into it, we changed our philosophy and started building the soil from the top down by using mulch. It works for us.

By the time I decided to do that, we'd been here several years and I had added tons of organic matter every year, but overall improvement was slow because prolonged, extreme heat breaks down more compost in a year than I can add manually. After the drought of 2003 (barely 18" of rainfall here that year), I added tons of bark directly to the soil in the fall and planted in the spring. I had no bark-related problems in 2004, and the only fertility issues I had related to very heavy rains (12" in June alone) that made it difficult for plant roots to take up nutrients. When the heavy rains went away in late June or early July, the plants improved very quickly and I felt like the bark I'd tilled directly into the soil was one reason the garden was so much better, although obviously greatly improved rainfall helped too.

After that, we started layering on mulch using any and every kind of organic matter we could find, including cardboard, newspaper, hay, straw, chopped/shredded leaves, bark mulch, composted manure, etc. For a couple of years, we rototilled it into the beds. However, I know repeated rototilling can damage soil structure and also can harm the earthworms and other desirable soil-dwelling creatures, so nowadays we mostly pile on the mulch and let it decompose in place. Eventually, the richer upper layers get mixed with the lower levels of soil....whether that occurs by us mixing the layers as we dig and plant, or via the earthworms and other decomposers doing their job. If using the bark hurts our garden, you certainly cannot tell it. Our soil is becoming positively rich both in appearance and in performance.

I would put the performance of our vegetable garden up against anyone's and would do so proudly. We ate all the fresh produce we wanted last year from April through almost December, and filled up 3 freezers plus a root cellar full of storage crops plus over 300 jars of canned foods, including tomato products, pepper products and jams and jellies. If our garden continues to perform like that, I'll continue to use wood mulch and will ignore anyone who says it isn't a good idea. : ) I believe in doing what works!

Our soil and water are very alklaline...in the 8.0 to 8.2 range, although we've improved the soil enough to get it down to the 6.8 to 7.2 range. (Can't do much about the water.) Hence, all my experience is with alkaline soil and I have no experience with acidic pHs. Maybe someone who has a more acid pH than we do can advise you about that.

I'd definitely follow their lime recommendation because soil that is too acidic isn't good for most vegetable plants.

Because your soil varies from sand to clay, you'll have to tailor your fertilizer accordingly. In its natural, unimproved state, clay is very, very mineral rich and fertile and sand is not. If your veggie beds have both sandy areas and clayey areas, I'd put the veggies that are known to thrive in lighter soil in the sandier areas. (For example, sweet potatoes, okra and black-eyed peas.)

And, by the way, did you see the news that OKC is getting a Whole Foods?

Dawn