I have grown a grapevine now for 4 years in my greenhouse. The root is outside the greenhouse, the vine is inside the greenhouse. All I get is bunches of small pea size grapes, very sweet but a lot of pips. Have taken advice over the years; pruning, thinning, feeding, watering, training, etc. But it is the same. I'm about giving up on it now. Gave it my all. What can be the problem with this vine, is it just a runt? Help!
Add your voice! Click below to answer. ThriftyFun is powered by your wisdom!
It's frustrating to try garden tips to no avail! You didn't mention soil, so I'll add here that too much nitrogen could be a culprit. However, assuming your grapes are Thompson, I'll venture that expectations are possibly not realistic. Industrial farmers use gibberellic acid (a synthetic plant growth regulator, i.e. hormone) to increase size and therefore marketability of table grapes -- this not available to home growers.
Make sure you are pruning the vine after the growing season is over. Letting the vine grow wild can be the cause of small grapes.
You do not grow the same type of grapevine and you do not grow a grapevine the same way if you want to have, big beautiful grapes to eat, grapes to make good wine, or if you want the grapevine to grow over an arbor. But in any case you should not grow a gravevine inside a greenhouse. The grapevines that produce wine are not good to eat. On a wine grapevine for the winter season we cut off all the branches and in the spring, out of the new branches starting from the floral buttons we leave only one branch or two branches at the most to grow along a wire and that's all. The grapevine that produces good quality wine is not left to climb it is maintained horizontal, it must receive all the nutrients and the whole field must receive as much sun as possible, that's why the plants are facing south in a slope to have no shadow. By law the grapes are picked up at a given time not earlier not later and for the grapes to receive as much sunlignt and warmth as possible we take off the leaves. In France it is forbiden to water the wine grapevines. It means that to make good wine you grow only a few grapes on the same plant, you do not water it to concentrate sugar as much as possible and you give it as much sun as possible.
In the U.S., we commonly see Thompson (Sultana) green grapes and Concord dark blue grapes sold as table grapes. There are probably other kinds too. I believe that nearly all our grape juice is made from the Concord variety.
From its original european/east asian wild ancestor called vitis vinifera was born a family of today something like 5000 to 6000 happy members. Obviously not only the father was a wanderer.
The most popular choices of grape vines to grow in a greenhouse are Thompson's Seedless, which produces a seedless green grape, and the Black Hamburg, which produces a larger, darker grape.
Watering
Grapes need a thorough watering once every week to 10 days in the growing season. Where the roots are outside the greenhouse, be guided by the weather and concentrate your watering in dry spells.
Fertilizer
When growth starts in the spring, feed every three weeks with a high potassium feed, such as tomato fertilizer. Applying the fertilizer so that each plant gets about 1 pound of nitrogen each year is ideal. A potassium-rich liquid feed to encourage flowering and fruiting in various plants, not just tomatoes. Take care to follow the instructions on the packet.
Mulch
Just before growth starts in the spring, mulch the rooting area with well-rotted manure. During the summer, it is a good idea to mulch the greenhouse borders with straw to keep the atmosphere dry. This will aid pollination of the vine flowers and subsequent fruit set.
Gardeners who live outside of 6-9 zones can grow grapes indoors in a greenhouse.
There are several reasons for grapevines producing small grapes:
Add your voice! Click below to answer. ThriftyFun is powered by your wisdom!
