Hmmmm - I know I answered this post, but obviously it never made it to the thread. So sorry. ;-)
There isn't much associated with screening granite or cherrystone over insect screen except for a little dust. I don't bother to collect this, it just falls on the lawn. Turface MVP or Allsport though, are different. What passes through insect screening often gets added to my raised beds. It's ideal as the 'sand' fraction in hypertufa projects, too. You can make some really cool troughs & planters from hypertufa! Finally, if I think I'm going to need a little extra water retention in a particular planting, I'll add the Turface fines to the 5:1:1 mix. FWIW - there would be no advantage in adding them to heavy soils based on peat, compost, coir, or other fine particulates.
Tapla, you wrote above that "FWIW - there would be no advantage in adding [peat, compost, coir, or other fine particulates] to heavy soils.
My yard has heavy clay soil. It isn't impenetrable, but it does hold a lot of moisture so that I can't grow anything that requires good drainage -- the plants might live through the first summer, but they die in the wet winter soil.
I can amend with compost (and I have a huge compost bin so I have a good source of that), but compost retains a lot of moisture too.
I'm going to try adding grit to break it up and get some air into the soild. Any other suggestions?
My post was in reference to container soils - I'm sorry I wasn't clear on that point. Incorporating larger particles of sand/grit into clay isn't very effective unless you're also incorporating OM and the soil can drain somewhere. Let's say that by some miracle you could suddenly create air spaces between the clay particles in your gardens/beds. On its face, that seems wonderful, but if the surrounding clay isn't amended or the garden/beds can't be drained to a lower spot, all those air spaces will simply fill up with water every time it rains & remain wet until the water is able to percolate through the soil or drain, with draining usually being much faster. Your soil can't drain unless the soil that surrounds it can drain or the water in your soil can flow from your plots to another spot. Terracing, trenching, french drains, sump holes, ... are all ways to help a nicely amended plot drain when it's surrounded by clay.
It might (might?) help in my situation, since my gardens are all on slopes, so standing water drains off readily -- but the clay acts like a sponge, holding in moisture. I just hate to go to the work (and expense) if it is doomed!
happy- consider a point made somewhere else--take a bowl of pudding and put marbles in it . You still have pudding, right?- even with marbles. I just don't know that you can realistically add enough grit to change the clay pudding into 'cake'...Of course, whatever tapla says on this , is the ultimate authority in my eyes.
Take a hammer or a file or a grinder and "bash&smash" up some red lava rock the sell as mulch , it's quicker, it's inexpensive, and it's easy even it reminds one of smashing things when one was a child"LOL
If you're on a slope, that's great! All you need to do is dig some narrow trenches that will drain your garden, then start adding OM to the rest of the garden. Ideally, the bottom of the trench would be clay, the lowest point in your garden, and the trench graded so there is at least a slight fall toward the lower spot where you want it to drain to. Inexpensive perforated drain tiles laid in the trench & covered with peastone would be the bomb if your property has an existing grade already. The biggest stumbling block would have been lack of a place to channel water to/away from your growing area(s), but you have that covered!
I agree with the "marble pudding" theory that gooey slush will eventually flow into all the voids between the marbles.
But in practice, it SEEMS that once the clay is amended ENOUGH to have some backbone (compost, fibers, OM, perhaps coarse sand or fine grit, fine roots), then it SEEMS that adding some coarse grit or bark chunks and nuggets lets me get a year or two of improved drainage if I "fluff it up" with a fork, then tamp it gently while not too moist. I seem to get something semi-stable that drains better than dead raw clay.
It never gets walked on, rained on heavily, or watered heavily.
The drainage improvement doesn't last for more than 1-2 years without being re-fluffed and compost added.
And it is totally dependent on a slope or trench to carry the draining water away from the bed.
And it is MUCH better if I can add and maintain enough OM that I have clayey loam as a base fraction, instead of clay.
The drainage is of course much better if the coarse matrix is such a large % of the mix that the remaining clay CAN'T fill all the voids, no matter how much it flows around. But even then, the clay fraction needs enough fiber, OM and sand that it doesn't flow easily. If it flows easily in a coarse matrix, it can just elluviate right out of the surface layers and form a hardpan at the bottom of the coarse layer: marble pudding or concrete, de4pnding on the water content.
I think the first word is also the last word with clay: you do need to add ENOUGH OM to turn it into good loam. Most of what I do is a series of temporary makeshifts to create "enough" drainage to grow things while I build up the OM in my soil. Left-over roots from last year are a big help!
This part of TX also has heavy clay soil. Over the years we have added expanded shale (looks like little rocks) and lots of bark chips, wood chips, horse manure, sand, compost and dried molasses. We have also tilled in green manures/cover crops. These additions have greatly improved our soil. In fact, when we have rain, it is a struggle to keep the growth under control, stuff grows like crazy.
But it wasn't so bad (cost wise) when spread over seven years. The main thing was the work in hauling and spreading the amendments (even that has an up side, we don't need to go to the gym if we're working in the garden : ) And then there's terra preta (is that spelled right?) which learned about from somebody talking about ancient farming practices. Since we don't have a way to burn wood under low oxygen conditions, we bought some already "cooked up" natural oak charcoal and crushed it into smaller pieces before adding it to the garden.
Based on the pudding-marble theory (got that from tapla tho he may not have used those exact items) and what I read about organic soil food web, I feel ever stronger about constantly adding OM. Terra preta (biochar) also sound good. This imitates natural cycles.
I have few scruples when it comes to making more soil barely adequate for makiing more raised beds!
I'll use 'fasty and dirty" methods until may yard has "near-soil " everywhere there is sun and no pre-existing flowering bush. Low juniper I'll keep tearin g out until park management c omes down on me harder.
After the "rescue" phase is over, and I'm maintaing an established garden, I'll use my pick and mattock less often. "Low till" sounds good some day, but right now, anything I don't turn and amend reverts to clay pudding below 6" in a year or two.
I have a "sharpshooter" sort of spade that I love, becuase I can reach down more than one foot, maybe 16", with one spadefull.
Tapla: Thanks for your supportive words! I've put in a bunch of French drains on the property, and I'm tired of doing that! So if I can't make it work by adding OM, then I'm just going to limit myself to plants that can grow in my awful conditions, at least on the front hill I am working in this fall!
On a slope, with HEAVY clay, part of the raised-bed-wall can be a berm of un-amended clay. That will probably act like terraces with concrete retaining walls for several years, until compost, worms, roots and watering soften the berms. (Just cut some slits and back-fill with gravel to let the water drain past the berms).
Then, either existing roots will hold it all in place, or it might start sliding downhill until it reaches boards held in place with stakes!
All of this sounds ssooooo familiar -- sticky clay, lousy drainage, etc. I just keep "messing" with it all in hopes that I will end up with nice planting areas. Tapla, what are sump holes that you mentioned above? mary
M - A sump hole is a hole dug in the clay, usually lined with a plastic crock, that water can be channeled to, then mechanically pumped out of or directed away from via natural drainage or a tile to a lower spot from which it can flow away from the planted area.
Al, that's something like I 'imagined' and in the past had given some thought to but couldn't figure out how to keep the hole from filling up with dirt, debris, etc. and considered using a clay flowerpot sunk into the ground. May try that; then I'll have to wait until sufficient rainfall to reevaluate my drainage/runoff problem areas.