What can you scrounge locally (even fossicking where the fly tippers work their foul habit)? Old paint pails with BIG holes for drainage (thumb-thick and about five of them) would give you your depth and the handles made shifting them relatively easy. Which would be useful as Saffron grow better if they're repotted annually - and have a rich mix with excellent drainage. If the plebeian past of old cleaned paint pails is a bit much then making a surround of recycled planks, refreshed with some paint, would disguise them and would hide the pot feet or the pebbles you stand the pots on to help them drain well. You'd probably get five to a pot. That would take you about 3.5 40L bags of potting mix. Less, if you plan to add sharp grit, about 3-5mm diameter, to the mix. I don't think I'd go for a washing machine bowl. They tend to have peculiar drainage problems (but that might just be me). And old tyres in stacks aren't as clever as they're made out to be. :-((( Old wooden boxes lined with thick plastic (such as the potting mix bags opened out and suitably holed) are a possible, if you can get them, and might even be 'art-y'. Or ancient polystyrene chilly bins/eskies - whatever it is you call those things with handles for taking drinks and ice-packs to the beach. And remember that they need a dry dormancy (although that might not be a problem with the heat waves the UK has been enduring in parts). As you have a reasonable number of bulbs you might want to risk a few in a shallower container, too. Just to see if you get flowers AND healthy bulb increase. Hope they do well for you. Those sharp orange-red tassels are something I look forward to each year. Pretty as.

I have lots of herb seeds to trade, including jalapeno, dill, lavender, oregano, basil. I can also mail out spearmint cuttings, which would grow nicely in any garden.

I had some in my yard and it did well. Unfortunately I had a lot of work done out front where the crocus were and they got trampled by the workmen. They don't seem to have survived. They are pretty and it's nice to get a crocus in the fall. This reminds me that I should get some more bulbs and re-plant. Now that things are finished out front, they should be safe. I guess I planted them originally in ignorance. Regular crocus do well in New England so at the time I assumed the saffron crocus would too. Seems to have been true.

If you're near Atlanta, there are patches of C. sativus in the Atlanta Botanical garden on both sides of a cement walk that's lined with tall crepe myrtles as you leave the entrance area and walk toward the big glass conservatory. Somehow they weren't touched with the redesign of the nearby rose garden. I'm in east TN and normal years my saffron crocus can be harvested mid October. Last year was very dry and they came later by about ten days. This year they are also very late.