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| Hi all
I've picked up a yard of compost for free from my city and am starting plant with it in raised beds.
What do I need to add for drainage? Thanks, Dan |
Follow-Up Postings:
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| You're dealing with hydrophobia, a tendency for the material to repel water when it dries down to under about 30% water content. You experience the same things with peat and pine bark. If you don't mind spending a few bucks, you can add calcined DE (diatomaceous earth) to the soil. It is an excellent soil amendment for raised beds. What it does is absorb water very quickly. That water is then able to diffuse into the surrounding material (compost). This 'breaks' the hydrophobic tendency of the soil material (usually, it's a dry crust that once broken allows water to be readily absorbed). 'Turface', is another excellent material to add to raised beds and does the same thing. Turface is calcined clay, and also holds water and nutrients very well. You're going to WANT a considerable mineral fraction (50% +) in your soil, if you want to minimize shrinkage (of the soil). Al |
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| What I have found over the years is that too dry compost (or peat moss or soil for that matter) can become hydrophobic and will initially repel water and all that is needed to solve that problem is patience and apply the water at a much gentler rate and mix the material a bit. I have never needed to purchase anything to help although sometimes it can take several hours (peat moss mostly) to get the material to accept thow moisture. |
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- Posted by toxcrusadr (My Page) on Fri, May 28, 10 at 16:46
| If you're using that compost 100% strength, tapla is right, you need some soil in there too and it will help that problem. Organic matter will continue to decompose and the elevation in your raised beds will drop accordingly. Nature normally does not grow things in 100% organic matter but in soil. A tip that I use for hard dry soil that sheds water is keep it mulched - I used grass/leaf mixture around the garden in summer. Water added on top of the mulch is diffused and slowly metered into the soil below, which will also accept it better because it hasn't been allowed to dry out and form a crust. Hope this helps. |
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| Sometimes a small amount of surfactant or wetting agent will help. You can buy expensive ones or use a small amount of shampoo (baby shampoo is supposed to be best, probably because it has few if any additives). |
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| I sometimes get compost like that nice slow watering and multch as others said really gets it done don't want to mulch put a blanket over the bed and start soaking |
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- Posted by borderbarb (My Page) on Fri, May 28, 10 at 23:41
| If your raised beds have sides that will hold the water, I agree that soaking again and again [with wetting agent] will do the trick. If the raised bed does not have sides, you might consider a misting sprinkler. Fine mist over time will not run off, but slowly soak in. |
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| If what you are trying to do (and that is what you should be trying to do) is get the compost wet you do not need something to improve drainage. Generally, patience will get the material wet, absorb moisture, so anything that is planted in that material can get the nutrients necessary to grow. Sometimes I have mixed into a bag of peat moss some hot water to get that dry and hydrophobic stuff wet. More often I will use slightly warm water to get my compost moist, putting the compost in a tub with no drain until it does absorb the water. Do not use hot water on compost since that can kill off some of the bacteria and fungi that help make compost valuable. Dry, and hydrophobic, soil simply needs time and it will eventually absorb the water you spray, gently, on it. |
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| .. I can attest to the grass clipping mulch effect 30 miles removed from the Mojave. I'm composting less and less with grass clippings use it more and more for mulching. Mulch with coffee grounds then grass clippings on top of that. The grass clippings keeps the coffee grounds from crusting and the worms really dig the coffee grounds moving it into the ground and soil to the top. to sense |
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| Hydrophobia only happens if you let it get as dry as a bone IME. Misting it will work much better than flooding. Just mist lightly a couple times and water thoroughly a short while after. Works for me with any substrate. Yes I know this thread is old! Just couldn't stand to leave the spammer on bottom and will spam them back since they posted their email. |
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| Tapla,Toxcrusadr, I got what you are saying & I agree with you. Question: Could one use coir instead of DE or is that a bad ideal? |
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| Coir, the shell of coconuts, can be just as hydrophobic as peat moss, dry compost, or even dry soil. Even most mulch material, if allowed to get too dry, will be hydrophobic. time and patience is needed when that happens. Adding a wetting agent (soap or detergent) usually is not necessary. A large enough volume of Diamotacious Earth, vermiculite, perlite, or even pea gravel, will aid water flow through the soil but will do nothing to help the soil hold moisture. |
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| Jolj - one of the primary attributes of coir and CHCs is that they DON'T become water-repellent like peat and pine bark. However, you should know that there are often salinity issues associated with these products, and they are both extremely high in K. Coir and calcined DE are 2 very different materials, but either WILL help to reduce a RB soil's tendency toward hydrophobia. One good way of helping to reduce the tendency of the surface of the soil to become water-repellent as it dries down below 30% water content is to include some material that never becomes water-repellent. The two that come to mind are Turface or stable forms of calcined DE (floor-dry/oil-dry - from auto-parts stores). For raised beds, one of the finer grades of Turface products would be a better choice than the MVP/Allsport we use so often in container soils - Quick Dry is what I'm thinking of, with all it's particles <30 mesh. Great for air porosity, yet holds lots of moisture internally ..... PLUS it has an excellent CEC. I think I'd prefer the 'Quick Dry' because I'm a little worried about the effects of the DE when the soil dries down. It is often used as a mechanical insecticide (even in food stuffs) and it's possible that w/o a lubricating coating of water on its surfaces that it could eliminate some forms of beneficial soil life (where Turface will not). Al
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| Thanks, kimmsr. tapla,Quick Dry Turface is what I will use. You have talked about it on another thread/forum. I have some red clay, but I am going with what you said. My garden is sandy loam, mostly sand. |
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- Posted by TheMasterGardener1 none (My Page) on Mon, Apr 25, 11 at 0:28
| OK OK... It starts with the compost. If you can take the everthing out of your bedds. When you compost you must add brown material(straw.branchs,ect..) then you would not of ran into this problem. Who cares what term it is.. you never have to worry cause now your composting right. So brown/dead material, green material like grass/vegs/fruits it all depends on what type of compost you want.Im about to post a treat about advanced composting to learn and help teach others about composting. Composting can save our earth. |
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