Frank, this is for you!
When you saw the milk crates keeping back the gravel from my FLOUT, you mentioned being interested in the use of baskets in the grow beds. I didn't say anything at the time but, I have what I've been calling a nursery bed.
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nursery bed (Medium).JPG [ 118.3 KiB | Viewed 3058 times ]
Based on the above mentioned comment, I thought you would be interested. This nursery bed is only about 6 1/2 inches deep and just under 4' wide (happens to be the width of the plywood as well as being wide enough to fit two seedling trays end to end across the width.) My original plan for this bed was to only fill it about half way with gravel and be able to set seed trays, plant pots etc filled with compost on it for starting seeds for the dirt garden as well as to plant out in the AP system. Been working quite well for that too. I've found though that one must be careful with the height at which one sets the trays or pots with compost as it wicks and can stay too wet or be left high and dry.
Now that my system is getting some maturity to it, I'm thinking I should reduce the amount of compost in the system so I've been working on using the gravel in the plant pots or other baskets I fine.
Comment on the Milk crates-I had to use really large chunks of lava rock on those milk crates to keep the smaller gravel back, this makes planting in such milk crates rather difficult. I would recommend a different kind of basket.
A note about your comment of perhaps using perlite. Beware! the stuff gets everywhere, just because it starts out too big to slip out of the basket, does not mean it will remain that way. Use with caution. That said, Gravel is heavy and a large basket or plant pot filled with it may not be strong enough to handle being lifted and moved with that gravel in it.
Anyway, I spent some time today harvesting stevia and as I often do, taking cuttings as I go. Here are a bunch of stevia cuttings planted in gravel in baskets and small plant pots set carefully at height in the nursery bed.
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close up baskets (Medium).JPG [ 112.3 KiB | Viewed 3306 times ]
Now there are some good things and bad things about such methods.
Good-things are very adjustable and kinda easy to re-arrange.
-doesn't take much space to start lots of plants
Bad-If using a variety of sizes and depths, digging around in the gravel to set things at the right height can be time consuming and messy.
-When you start lots of plants, you need to be ready to do something with them when they are ready!
-It requires more materials, namely the pots/baskets. Most of these will deteriorate over time in the sun and being handled with heavy stuff in them.
-Most baskets and pots taper in at the bottom so there will likely be wasted space down around the bottoms of the baskets/pots. If you are not doing the gravel around the outsides of the baskets/pots, there will be water space there that isn't being utilized as filtration.
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sinking pots (Medium).JPG [ 118.63 KiB | Viewed 3053 times ]
Now my nails are shot but I still kinda enjoy digging around in the gravel. Gives me a chance to inspect some of the worms.
There are a fair lot of them in there and I don't think I hurt too many of them too badly digging around.
