Where my garden is there are a lot of walnut trees and I was told that they affect the growth of cucumbers and tomatoes, which I always have trouble growing. Is this true?
If they are black walnuts, then yes, this is true. This article has more information:
What is the best amount of sun for cucumbers? We live in the mid south.
They will need about 5-6 hours of full sun.
When is a good time to transplant cucumbers that have been started from seed? When would be a good time to transplant to individual pots to get the best growth for planting outside (they seem to die out on me when I plant small seedlings outside in the garden)?
This article will help with that: https://www.gardeningknowhow.com/garden-how-to/seeds/when-to-transplant-a-seedling-plant-into-the-garden.htm
This article may also help: https://www.gardeningknowhow.com/edible/vegetables/cucumber/tips-for-growing-cucumbers.htm
My seedlings are coming along nicely in the Jiffy Pellet Tray System and under florescent light bulbs. The cucumbers are the tallest and most impressive with a third leaf and lots of roots pushing through the netting of the pellets. I had to move them because they were shading the other seedlings! Question: Do they need to be transplanted NOW or are they okay to wait another week (our last frost date is April 3-10)?
If your 10 day forecast does not show cold weather, you can transplant now. If it does, as long as you keep them well watered, they can stay inside for another week.
Our cucumber plants are turning yellow at only a month old.
They are lacking fertilizer, most likely. Give them some weak fertilizer, 1/4-1/2 the recommended rate on the package.
I have recently errected a small lean-to greenhouse and would like to grow cucumbers in a grow bag this year. I intend to grow them against the wall in the greenhouse, so would it be better to fix trellising to the wall and train them up this, or should I put canes in the grow bag like I do for tomatoes or would strong string be the best? I welcome any help and tips to enable me to have a successful crop. Thanks, Dorzy.
I would use a trellis. You will find this article interesting:
I seem NOT to have a green thumb. People tell me that they can't even give away all their vegetables. Last year I had two cucumbers. White flies ruined my tomatoes. My zucchini wilts (sucked dry), same with crookneck squash. I have tried pots and planting in different spots. I don't know what to next, except not to have a garden this year. If you have an suggestions, my ears are open. Also, I tried the Topsy-Turvy with the three openings (doesn't work) and the strawberry one didn't work either. Even when I tried to grow strawberries in a hanging pot, I had hardly and they were really small. HELP!
Don't give up yet.
It sounds like you have several pest issues in the garden. For the pests, such as the whitefly, cucumber beetle and vine borer (which is what took out your tomatoes, cucumber and squash plants), I would recommend treating your garden with neem oil. Organic and safe, but very effective on these pests. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
The strawberries were not your fault. They just do not produce well until the second year and the companies that sell those hangers do not mention this.
Gardening has a learning curve and you will get results the more you do it.