>> glacier slurry which has a LOT of small rocks tightly compressed together. Once I break up the soil for planting, I leave those rocks in the bed because I honestly believe they help with the drainage in my clay soil.

I agree with you, but also with Al. If the rest of your mix includes clay or silt in a form that is not tightly bound into small peds or clods, heavy watering CAN wash the clayey or silt into the crevices between rocks, gravel and grit. That would plug the soil up tightly also.

Probably you have amended your clay with enough organic matter that it "holds together" instead of washing out freely and turning the bottom of each bed into clay pudding or concrete, and leaving the upper bed as sandy gravel.

P.S. Another theory of mine is that medium sand has SOME value in loosening clay soil IF there is also almost enoough organic matter and grit or fibers present. Without sand, the clay is too sticky to be broken up finely no matter how you work with tiller, garden fork or broad fork.

When fine sand is present, the clay is more firable, I guess at the boundaries between clay and sand particle. Now you can "fluff it up" - break it up into small clods, or create small channels and voids which MIGHT stay open if other things are OK.

Pure clay is very fluid and sticky. A clod of wet clay can deform and flow. It will flow into gaps between it and the next clod, then stick, so that an open matrix squeezes the air voids OUT and what is left all sticks together in one big blob of glue.

But if the clay has enough organic fibers (like bark or peat), plus grit (like tiny bark nuggets, crush rock and coarse sand), then each clayey clod may have enoguh STIFFNESS that it won't deform and merge with every other clod surrounding it.

I realized that when I had "fluffed up" some clay I had amended with a LOT of grit, to create drainage for bulbs. When I firmed down the mix I had just fluffed up, instead of silently compressing back into clay pudding, it made a gritty crunching sound afetr compressing a little, and then resisted being firmed, while it still had some open structure.

That "crunching" was probably from grit touching grit, and resisting compression directly. But I thought that some of it was from small clay balls with enough sand and grit and bark fibers mixed inside them to resist deformation. Then their surfaces, with more fine and medium sand grains, crunched against other little clay balls.

But sand and grit won't help clay much by themselves. They need at least a bare minimum of organic matter mixed with the clay, plus artful mixing, fluffing and firming while not-quite-dry to prevent the classic formula of "clay plus sand plus grit equals concrete". And somehow the organic matter prevents watering from elluviating * the clay and silt particles into the bottom of pot, forming clay pudding / concrete.

That's my theory of clay plus sand plus grit plus ORGANIC MATTER, anyway.

* http://wiki.answers.com/Q/What...

Rick, It's interesting how we all learn different ways to manage the soil we have in our gardens. When I first started this garden, I did put organic material in my planting holes. Ooops ! When the organic material decomposed, the plants sunk ... not good. Now, I only put the organic materials on top of the soil. It still improves the soil over time.

This year, I am adding some sandy loam to the beds, but in small amounts because I don't want to create concrete. It's hard enough to garden in glacier slurry.

I think the key to any successful container gardening is drainage. It was your comment about adding bark nuggets to your mix that made the light bulb go off in my head to let me know the "why" leaving small rocks in my native soil is working.

For container gardening, the soil mix is impacted by the ambient air temperatures in your climate as well as the soil mixture. I have to use a heavier soil mixture in my hot and dry climate to retain moisture than a gardener in a more humid climate should use because just the fact that the air around the containers is dry will wick the water out of the container faster.

But back to Rookie's original question:



You said you planted your seeds in a mix of " in a mixture of soil, husk charcoal and manure (3:1:1)". I haven't grown many things from seed, but have propagated a lot of rose cuttings. I would never add any manure to the planting mix for any of the cuttings for two reasons: 1) most manures are simply too strong for young roots and will burn them, so even if your plants were not overly moist, you have added an element that can very possibly harm the new roots; and 2) manures, and in fact all plant foods, add salt to the soil.

When the soil... or planting medium ... contains more salts than what is naturally found in the cells of a plant, nature automatically tries to equalize the imbalance and, in this case, will pull water from the new roots to the soils because the soils contain less moisture than the plant cells, so the roots lose water. Clearly that is not going to help a new plant grow into a healthy plant.

For my rose cuttings, after they have produced new top growth, I will fertilize with a very, very weak solution of liquid fertilizer to bring them forward to where I can plant them into a larger container.

As you can see, there are a lot of variables. However, I think the best answer to your question was Chelle's when she said, "Some plants are more demanding than others; even within the same general group." I know with roses, some roses root like fire while others are incredibly difficult to propagate. So, I can't handle all of them exactly the same way. This may be true about planting different kinds of morning glory seeds.

Smiles,
Lyn

>> have to use a heavier soil mixture in my hot and dry climate to retain moisture

I understand! Fast drainage usually means less water retention, and then more-frequent waterings. Drippers or sprayers on a timer, watering once or twice every day, would be one way to handle extremely fast-draining containers in hot, dry areas.