For fruit trees I’ve thought a lot about using small quartz rocks over fabric for a permanent solution that also offers the trees reflected light to potentially help fruit quality. They are heavy and not cheap so I’ve not gotten around to trying it, but price and effort might actually be less over the long haul. Here in the humid region there may be advantages to rocks that don’t hold water, reducing humidity and the reservoir of available water.
I have grown on black plastic mesh for about 15 years with good success for some crops but a few that should never be grown that way. Squash bugs love to hide under the fabric and come out to feed on squash plants. The fabric makes it difficult to spray for them. Butternut family (Moschata) does fine on plastic, but Pepo and Maxima do not. This may be a regional issue that does not occur in other climates. I am in North Alabama so have a hot humid climate.
Crops that do good to very good on plastic mesh include: Watermelon, Cantaloupe, Cucumber, C. Moschata, gourds, and most other vining plants.
Crops that should not be grown on plastic mesh include: lettuce, carrots, radishes, onions, and most other plants that would normally be grown in a bed.
Standard row crops get mixed benefits from plastic mesh. Corn, beans, okra, and other crops that are easily cultured in rows are usually easier to use tilling and weeding. I have grown tomatoes, peppers, and eggplant on plastic with reasonably good results but the benefits are just not enough to justify the trouble of setting up the plastic. Part of this comes down to me enjoying using my tillers in the garden.
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I had wondered about using rocks around my house instead of mulch. Mulch never lasts and it looks great for the first month or so. I see a lot more businesses using rocks now instead of mulch.
My main question would be what type of effect would those rocks be on younger trees ( say 1-5 year old)? Would the hot summer heat and sun back the root system? I would try it out on some more established fruit trees first if I had some bigger ones to experiment with. I do like that idea though. Thanks for bringing that up as an alternative to the landscaping fabric. I think these restaurants are saving a lot of money in maintenance using those rocks. Plus it looks nice all year round.
Not instead of landscape fabric- over landscape fabric Once and done.
I don’t see how small rocks or gravel would be damaging to fruit trees in this context except maybe in low humid southern regions or anywhere that sunburn is a problem on fruit. Otherwise the reflective properties of light colored rock should enhance fruit quality. Actually, a layer of gravel below and small rocks on top of fabric might be the perfect formula because the gravel would tend to subdue rodent activity under the fabric, which is often a problem.
It’s funny but I started to write the comment before this one months ago and didn’t realize I hadn’t submitted it.
I constantly curse the rocks that someone placed all over my property, around every tree and building. They get all over the place and obstruct weeding and maintenance.
When we bought our place there were rocks around things with landscaping fabric underneath. The weeds still come through eventually. We’ve gotten rid of most of them now. They also end up in the lawn, not sure how, but a nuisance.
Rocks as “mulch” can be useful. Around houses/buildings in fire prone areas they help protect the structures considerably, but only if you don’t plant trees and bushes in them. In fact, they are required in some locales for new construction around here.
Around trees in an orchard, I have my doubts. It basically means there will be no further organic matter going into the soil, which might be OK if you started with great soil but not ideal if you didn’t. Rocks also tend to heat the soil, which in many climates will tend to kill much of the life that was living there, at least in the hotter months.
Regardless of what you do around your trees, weeds and grass will eventually come back. Some treatments will keep them away longer than others but sooner or later you will need to weed and renew or redo the treatment.
First of all, roots generate organic matter, and secondly, I’m talking only about rings under trees that would not extend beyond about 3’ from trunks, leaving the majority of soil the trees are rooted in unaffected.
That is my concern. Not so much when they get bigger and the actual tree canape shades the area of the rocks. It is when the trees are younger and a lot smaller. The heat and direct sun the smaller trees get makes me worry about the heat drying up or killing the smaller roots.
i also agree mulching is the way to go. i have a firewood business that loads my truck for free of all the hardwood chips i need. i add 3in . every spring after i fertilize. retains moisture naturally and improves your soil. breaks down by the next spring into nice black soil, full of worms. arborists in the area would be glad to bring you a couple loads for free also, just make sure there isn’t cedar or b. walnut in there. 2xs a year i spray weed killer on the edges of the wood chips as the grass starts to grow into it. prevents it from getting into the chips and get established.
Why would crushed white stone heat the soil? Even black plastic, which does heat soil- partially because it traps the steam it makes and partially because it is black, only can kill a couple inches down.
Soil insulates too.
I managed apple trees and one peach for years that were in containers, but most roots had grown into the ground under light grey gravel. The trees thrived and achieved very high quality fruit. A Madison peach tree in the mix consistently achieved higher brix than my own tree of the same variety, even though it was equally vigorous- suggesting it may have been the reflected light that improved the quality of fruit.
That tree was 22 years old and still pushing out lots of long vigorous shoots over the entire length of scaffolds last I saw it. The apples are on M7 and about 80 years old and thriving.
Black plastic needs to have direct contact with the soil to meaningfully warm it. As in, a tilled and shaped raised bed laid by a tractor with black plastic mulch that shrinks tight after application. Black ground cover laid down with just a slight air gap keeps the soil cooler during the hottest part of the day, according to my own unscientific observation of sticking my hand under it, it does get better soil contact after a while though. The air above black ground cover is hotter, and that can be rough on young new transplants, I spray a few coats of surround in a 3ft. diameter ring around baby figs to reduce stress. To really heat the soil you need to use clear plastic, but some weeds can still grow under it and condensation can form which messes things up.
my father used to grow the best garden in town planting in heavy black plastic. were he put stones to hold it down, he would put slits under them and push them in so it made a depression to catch the rain. rarely did he have to water. mulching works good to improve soil and for trees and perennial bushes ,but for ease and convenince, black plastic was the way to go. it also increased the plant growth by heating the soil up more quickly, which up north here increased the growing season. used the same plastic for many many years.
you will always battle leaves and debris getting in there and weeds growing in between. they are great at keeping in the moisture and help heat the soil in the spring. just would need a spray of weed killer once and awhile to knock the weeds down.
I’m not sure if that is true, but you are certainly correct that it will warm soil more if it is flat against the ground based not on my experience but this linked article (I admit it, I never noticed or did a comparison even though I have occasionally used black plastic for tomatoes- mostly I’ve used fabric, though, which tends to lay flat).
According to this, the affect is only significant in the top two inches of soil, but that can be extremely helpful in spring. However, I don’t think it would significantly affect soil biology below the highly heated part- in spring it would probably enhance the life in the soil.
http://www.uvm.edu/vtvegandberry/factsheets/plasticprimer.html
The article does say black plastic mulch needs to be flat and tight “to the ground” to provide the warming benefit. That’s what I’m talking about, I don’t think it can be laid down by hand and achieve that type of contact right away even with tedious precision leveling, even the tractor has trouble getting complete contact with plastic mulch if there are more than a few clods even though the mulch is firmed down by a heavy roller onto the bed…
I think what ends up sticking ground cover or thick plastic to the soil is heavy rain liquifying the top layer, so it might start warming sooner or later depending on the weather. But even a finely raked seebed will prevent most contact at first, think of how little actual contact there would be between a layer of ball bearings and a board. Heat will conduct from the plastic to soil it is touching more readily than to air, but because heat rises it does not conduct downwards through even through a small layer of air.
“That’s why black plastic must be laid flat and tight to the ground if it is to provide the maximum warming effect.”
The statements aren’t equivalent, and I think gardeners should see for themselves if it is so hard to lay it flat- the article is very unclear of the precise extent of the difference.
I wonder how black plastic bags filled with some water would work? That would get the plastic against the ground and keep the soil warmer into the night.
I understand it is a bit of a leap if you are not intimately familiar with how black plastic mulch is laid down mechanically which is the context of the article. And I do hope people investigate for themselves, it was a bit of an epiphany for me that the soil under black ground cover (that was flat on level ground but not actually stuck to it yet) was cooler than bare soil (and thinking about that: the darker the soil, the less warming black plastic delivers vs bare soil). It really helped me work up how to best use ground cover to protect fig trees in compost socks, last year they woke up very early and I attributed that to direct contact between the cover and the socks/soil/roots transmitting heat so I tried to mitigate that this year with a layer of air and am about 95% confident I’ve got it under control.
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And I do appreciate your observation, which I failed to make when I used plastic.
I love to hear of other people’s observations- best thing about this forum.
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I was curious on temps under plastic in my garden back in late Nov. I had some greens and carrots on black plastic and others on white. I expected the ones on black to grow more in cold weather but it wasn’t happening. Turns out temps were about the same for both colors down a couple of inches. Only right up on the surface was black warmer than white. Both colors were cooler than bare soil at the surface and about the same deeper down, at least mid-day on a sunny day. My plastic is the thin stuff just laying on flat ground with bricks holding the edges. I would like to get some clear plastic next time. Maybe I’ll try it to start some corn in early march. Seems like it could help with frost protection by banking some heat for nighttime release under a row cover. I rarely see higher temp under row cover without providing a heat source, which runs contrary to manufacturer claims and is a discussion for another thread.
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