You might be able to pick them as early as mid-September, but they might not ripen until the first two weeks of October. Chardonnay grapes, which also grow in USDA zones 7 through 10, are early grapes that typically ripen in mid-August.

In California some sparkling wine grapes are harvested in late July to early August at a slightly unripe point to help maintain acidity in the wine. The majority of Northern Hemisphere harvesting occurs in late August to early October with some late harvest wine grapes being harvested throughout the autumn.

The beginning of ripening, grape veraison is the time in a vine’s annual lifecycle when the red grapes change from green to purple hues. Veraison, French for the “onset of ripening,” usually begins in July in moderate weather years, but in cooler vintages, red grapes sometimes don’t start changing color until August.

Too much fertilizer: If you’ve given your grapevine too much nitrogen fertilizer, this can result in lush growth of the foliage and no fruit. This also happens if there is too much nitrogen in the soil. Not enough sunlight from improper pruning: Grapevines need full sun, all over, for a full harvest.

Installing bird netting just before the grapes begin to ripen is the surest way to protect grape vines from birds.

1. Measure the distance from the ground, over the top of the grape vines and down to the ground on the other side.
2. Unfold the net and stretch it out along the row of grapes you wish to net.

The plants also require extensive pruning each spring. After all that love and attention, it would be heartbreaking to see wildlife eat your grape crop before you had a chance to get a taste. Covering your vines with nets as the grape bunches develop can keep some of the pests from stealing your harvest.

Cover your grape vines with fine mesh netting to protect the grapes. The mesh should be between 0.5 to 0.8 millimetres (0.020 to 0.031 in) to protect the grapes from flies, moths, beetles, and other larger insects. The mesh creates a barrier and reduces the need to use chemicals.

Sucking insects, such as aphids, will attack the terminal parts of the plant. Horticultural oils and insecticidal soaps, or neem oil, may be effective in combating these common types of insects.

Soapy Water Most any home improvement or lawn and garden store will carry insecticidal soap that is labeled as organic or natural. These soaps can be sprayed on the vine and will suffocate many species of potentially damaging insects and may help control fungal or bacterial issues as well.