You could decide that you have too many plants, or you could decide that your trellis is too small. I would just put stakes in the ground a foot or so away from and on each side of the trellis, and run a few strings to the trellis. Make the trellis bigger. Your main problem may just be self-shading.

Unfortunately making the trellis bigger isn’t an option as this is a squarefoot Garden and there’s already established plants surrounding the cucumbers. And moving around the bed would be impossible if I let the plants leave the container entirely. Sounds to me like you’re saying that’s that they are probably too crowded?

You say you thought this was plenty of space. To my knowledge, cukes are ordinarily supposed to be planted 18-36 inches apart. You have them 8 inches apart. Square foot gardening is supposed to be a lot denser though, and if that's what it says to do for that kind of gardening, and you're committed to that kind of gardening, then I'd just go for it, and hope for the best. I've always been a little skeptical about the plant densities suggested for square foot gardening.

Way too crowded for me based on the photo. I agree with Dan that 18-36" spacing is normal. I use 24" so that would be 2 plants max in that space. JMO

Dave

Commercial spacing of pickling or slicing cukes is quite dense, 12, 6, even 3 inches between plants in-row. Row spacing is much larger.

Thanks. Yes 2 trellised vines per square is what’s recommended, but simply saying “trellised” is pretty ambiguous as a trellis could be 2 feet tall, it could be 8 feet tall. So while I’m confident there’s enough soil space and nutrients to go around, I’m concerned about the available climbing space. Since I’ve never grown them I have no idea how big the vines get. Is it ok if they grow over and weave in and out of one another? They’re already covered in flowers, once they fruit will the vine growth slow? A friend suggested I prune them if they became unruly, but I’d be worried that they would stop fruiting if I did that, which is why I was debating thinning them.

I think the height of the trellis is important just in regard to shading. A more important question is how much soil each plant has available to it. With plants only eight inches apart, I'd have to assume they are competing with each other for nutrients. The root ball of a mature plant is at least a few feet across. Though maybe you're adding enough fertilizer to avoid that problem.

As to trellis height and shading, if you don't have room to expand the trellis laterally, then just expand it vertically with tall stakes. Two six-foot T-posts would do it nicely.

Your cuke trellis is a lot less crowded than mine. A 5' tall x 12' long wire fencing held in place by rebar stakes. Cuke plants are about 8" apart and now over the top of the trellis with lower offshoots trailing over the ground. No real pest or disease problems other than hunting down the ripe cukes hiding amongst the foliage.

Thanks that makes sense. I’ll find someway to do add more vertical climbing area in the space I have. I can’t block my walking path or crowd the space around it since there’s already established plants there, I’m thinking of trying the stakes at the tall end of the trellis (it’s a lean to). So if they do become too big for the trellis I will train them to climb upwards instead of outwards. I feel better knowing others have had success in similar plantings! I’d hate to have to pull any of these at this point.

Hi, I am doing SFG also, and have a similar problem. I think I have the same trellis as you - actually not, I have the same width but it is a two sided trellis. I put mine diagonally across a 4x4 bed and put two plants on each side. Because in the past two years I have lost my cucumbers and zucchini to pests, I decided to companion plant nasturtiums with both my cucumbers and zucchini. So, no pests this year, but everything is going gangbusters including the nasturtiums. In fact the nasturtiums are taking over the trellis ladder. In my case I cut back some of the flower vines. Since everything looks healthy, I am going to assume that this is success. Your cucumber plants look nice and healthy too But next year, I'm going to plant the nasturtiums in a pot outside the box with its own obelisk.

Did your nasturtiums actually trap the pests that would have gone to the cukes, or did the pests just not show up? Sounds like the nasturtiums are doing pretty well. Nasturtiums don't repel pests. They attract them.

Barbara: Yes I read the nasturtiums repel squash bugs. I used marigolds myself. I have to keep cutting them back hard because they also want to crowd everything. Can’t hurt to prune them if they’re getting in the way of your crops!

I think it's true that nasturiums do repel squash bugs, if that's what your problem was. But they're a trap crop for everything else.

They will definitely be crowded. In a square foot garden a bush type variety would be better. Just be sure to pay attention to cucumber beetles. They enjoy crowded plants. As long as there is air flow in between them you should be ok. I over crowd mine because I have little space in the city and I want as big of crop as I can get for pickling.

@daninthedirt

The way the companion process works for cucumbers and nasturtiums: squash beetles don't like nasturtiums so they don't come near. I haven't seen a squash beetle. So instead of the cucumber leaves dying off before they produce flowers, the leaves grow lushly with many flowers. I have to do some more pruning of both the cucumber leaves and the nasturtiums.

Yes, nasturtiums are effective trap crops for aphids, and all the aphid predators that go with them. I'm skeptical about trap crops in general, because if they are close to your vegetable, they just attract more of what you're trying to trap to the vicinity. Your vegetable just becomes a side-dish for lots more of them, instead of a main dish for fewer of them.

Sorry this might be even further off the discussion but, Are squash bugs really that much of a problem with cukes? Now If you told me the nasturtiums attracted cuke beetles I would plant an entire plot of that trap crop.

Yes, but I think they like squash and pumpkins better. Now, if you do plant a trap crop, don't plant it next to your veggies! Plant it far away.