I recently bought half of the empty lot next door - shared the other half with the neighbor. I'm in the process of turning it into a veggie garden with several fruit trees. Well, after buying the lot, putting up a fence, building the raised beds, the money was sort of tight. I needed 6 yards of soil delivered for the raised beds, and called around for prices, anywhere from $125 to $600. I knew I had a good amount of compost, so I bought the cheapest I could find. The soil looked pretty good, although it did have some shells & rocks in it. Not too sandy, not too clay-y. Got it all spread out among the beds, incorporated some rock dust and about 3" of compost. And them we had rain, And more rain. Now, when the soil dries after a rain, it forms a crust on top. A really hard crust. It can be broken up with a cultivator, but not completely. I'm afraid my seeds may have a hard time sprouting. When I planted the bean & squash seeds, I covered them with potting mix.
I've never seen this before. New Orleans generally has pretty good soil and this has never happened to me before. I'm sure one of the answers is to add more compost, but right now, my compost bins are still cooking and not ready for use. I'm going to heavily mulch once the plants are in, but that doesn't help the seedlings.
jomoncon - the soil you purchased could be the problem.
To stop it from crusting, purchase some wheat straw bales (NOT HAY BALES.) In the fall you could collect free leaves and use your mower to mulch them into small particles. Leaves break down into free soil. This is what I've been doing for the past six years.
Some store-bought potting mix is mostly peat moss, which itself can form a crusty top on the soil surface. . . Please note I am up in Michigan, so can't really opine about your soil or what is sold in stores in your area.
Thanks for the ideas. I've been mulching the transplants with pine needles & that seems to help. The seeds that haven't sprouted yet are simply getting a light sprinkling at least once a day to break down the crust. Some are sprouting, so as soon as they're up I'll mulch them also.
Whatever is causing this, I'm sure mulch & more compost will help. I have 8 chickens, so I get a goodly amount of manure, and I have bags of leaves collected. I recently did my spring cleaning of the chicken coop, but that stuff needs to sit for at least another month. Another compost bin is almost full, so it needs to sit for another 2 months. So in a few months, I'll have a good deal more compost to use.
Pounding rain will break down the structure of many soils. Too bad the mulch could not have gone on before sowing the seeds, but I don't do that either. I would worry about seedlings pushing through the mulch.
If hand-sowing small areas, you could push mulch aside right arolund each seed, but then soil woluld stikll crust where you wnat it least: right on top of the seed.
More organic matter might have helped, maybe only a little. But rain pounding on finely raked soil is just like "working" soil when it's wet.
Maybe sowing right after raking, then covering with a floating row cover before any rain would have helped ... somewhat.
This isn't practical if you're sowing large areas, but you can scrape rows slightly deeper than you want to sow, and cover that row with 1/8" - 1/4" vermiculite and some coarse sand or fine crushed stone. Drop seeds on top. Then cover with more vermiculite & coarse sand ... that won't crust.
Or germinate everythning indoors or under plastic, in trays of cells, and laboriusly set out every seedling by hand.
sallyg, That's my plan: mulch & more compost. I think in a year or so everything will be much better.
Some seeds are starting to sprout through the crusts. As soon as they're up & a good size, they'll get ground up leaves. The other larger plants are getting pine needle mulch.
I was just so worried when I first saw the crusts. I'd never had it happen before, but then, I'd never bought such cheap soil. But, money's tight right now. I'll work with what I have & concentrate on making it better.