I want to work on absolute shade tolerance. It should be possible to get plants that actually thrive in full shade rather than just tolerate it.
I was thinking of starting with greens as an easy transition. Anything else I should try? I’m going to do full shade with perfect soil and water, but I can get the hydroponics version started now.
Suggestions?
Photosynthesis is based on carbon dioxyd, water and light, with light as the source of energy allowing the recombination of water and carbon dioxyd into plant material. So what, in your idea, would be the energy source of the plants you would grow under “full shade” ?
If you wanted to expand beyond greens, a good starting place might be tropical or subtropical understory fruiting plants. Also, Native Seeds/Search did a trial last year and confirmed reports that Ciudad Victoria tomato thrives under 50% shade. I’ve not done a lot of study of ancestral tomatoes, but a redomestication-type project could be successful with some crops.
What about improving edible wild plants that do well in shade to be more palatable and easier harvest.
Many plants already do this, but most of them aren’t domesticated. I suspect that if I select for plants that do best in shade they would start to adjust and use the light they do get more efficiently.
Any suggestions?
If you’re talking about dense shade under mature deciduous trees, in a temperate latitude, I’d suggest focusing on understory shrubs such as hazelnut or wild plum, or understory trees such as redbud and pawpaw, or on spring/fall ephemerals such as ramps, ginseng, etc. Hardy passionfruit and hardy kiwi are shade tolerant vines that grow up to heights and find little shafts of light.
I don’t think you’re likely to have much success at all in dense shade of conifers. I would focus on deciduous trees.
If you’re talking about part-shade, there are lots of options. Raspberries, blackberries, come to mind. Kale is quite adaptable if you disturb the ground and scatter copious seed. Scarlet runner beans can grow up into little shafts of light (start in containers and give them time to get to a good size, then they won’t struggle as much). Tomatoes are surprisingly adaptable to part shade. Let them drop some fruit on the ground so there will be volunteers next year. Cucurbits have large leaves and vining habits so can be encouraged to grow up into shafts of light as well.
I’m very interested in this kind of project, as half of my garden only gets 4 hours of direct sunlight in summer. This year, I’m going to try C. moschata in that section and hopefully I’ll end up with some squash that thrive in partial shade.
That’s a good place to do such a selection! My garden is similar. I find that 4 hours of direct sun can be enough to get a harvest from full-sun crops such as corn and squash, but barely. It will put selective pressure on them. I did manage to harvest some moschata squash.
Slight delay as the temps are supposed to reach low single digits (-15 to -20 C)in the next few days.
My hydroponics has four tanks, which get 6, 4, 2 and 0 hours of sun in the summer. I plan to plant all four with lettuce and arugula (that’s what I have seeds for). Anything that survives the lower light tanks will be planted out in the garden to get seeds, then replanted in the same conditions.
I hope that after 3 or 4 generations I will start to see adaptation and seeding under low light conditions.
In the meantime I ran across something interesting among my tomatoes. Usually they get tall almost immediately, since I don’t use supplemental light. But these few seem to be staying small but still appear healthy.
Possible shade tolerant tomatoes?
Some perennial vegetables I grow in full shade:
Hosta - see my breeding project here: Large-leaved Hosta for spring-forcing shoots
Hablitzia - see a short notice here: My favorite perennial vegetables
Adding shade-tolerant fruiting trees and shrubs would be neat, too. Obviously pawpaws would be a great choice. Here are a few more ideas from my notes:
All of those have edible fruit that is supposed to be pretty good. (Extremely good in the case of Virginia strawberry; just very small.)
Do any of those float your boat?
Ooh, if runner beans can do okay starting in shade, that’s likely to be helpful for me. My summers are very hot and dry, and I’ve been struggling to get runner beans to succeed. I’ve been hoping if I grew them on the south side of some very tall trees, that would be a promising microclimate for them.
