We just bought a house that has grapes growing in the backyard and we are trying to figure out if they are edible.
It is hard to know what the exact type of grape it is, but it does appear to be a cultivated, edible variety. However, just to be sure, I would take a sample to your local extension office. There are a lot of look alikes in the plant world, many poisonous.
This article will help you to care for grape vines: https://www.gardeningknowhow.com/edible/fruits/grapes/growing-grapevines.htm
In the spring - I took a stalk clipping from a grape vine - rooted it in water and then planted it in a small garden pot. It is growing well and adding green leaves. Should it be planted outside to overwinter till the spring or should I keep it in the house over the winter.
Keeping it inside under horticultural lamps will, definitely, give it a boost over the Winter. Doing so will give you an advantage when it comes to next year's planting.
Here is an article that will help you to keep it in container:
https://www.gardeningknowhow.com/edible/fruits/grapes/container-grown-grapes.htm
Is it possible to grow grapes in containers or do they need to be planted in beds? Thank you
Yes, you can! Here's an article that will tell you how to do it:
https://www.gardeningknowhow.com/edible/fruits/grapes/container-grown-grapes.htm
It's growing largely no flowers from past 3 years.
Our experts say to fertilize your grapes with a product high in phosphorus, which is the middle number on the fertilizer ratio, such as 10/20/10. Do a soil test to determine what is needed, if possible. Your vines may only need a light feeding of compost tea and mulch during winter.
I think this article should answer your questions: https://www.gardeningknowhow.com/edible/fruits/grapes/how-to-get-grapes-on-vines.htm
i read the over wintering article. says to lay your plants down and cover in ditches. Is that necessary in zone 5b? And how can you lay down mature grape vines because they are so thick and not flexible near the bottoms
If your vines are hardy to zone 5 they should be able to overwinter just fine without a lot of cover. You could try the simpler method of mounding soil up around the base of the vines, rather than trying to lay them down.
https://www.gardeningknowhow.com/edible/fruits/grapes/grape-vine-winter-care.htm
one It is planted on a south facing wall which is part of my garage. I prune it to 2 buds in the dormant season . I have been advised not to feed it as all the goodness will go to producing leaves.I would be grateful for your advice please .
Likely, since it doesn't get fed, it is needing nutrients.
The best thing to do will be to test the soil. This will tell you the pH of the soil and nutrient content. With these two pieces of information, you can amend your soil back to within the proper ranges.
Feeding with an all purpose without testing the soil can lead to a nitrogen build up. This will halt fruiting and produce lush vegetative growth. But deficiencies in potassium and phosphorus, and even sometimes a deficiency in micro and trace elements will cause fruiting issues.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm
This article will help you to feed grapes, properly:
https://www.gardeningknowhow.com/edible/fruits/grapes/how-to-fertilize-grapes.htm
Both stems look health and are the same height
Yes, cut one off. Here is more information in training the vines.
https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1657-2015.pdf