DIY Network

Care and Harvesting Kelly Givens has special care and harvesting tips for grapes. From "Fresh From the Orchard" episode DFFO-110

Kelly Givens and her guest, Jack Mandula, have some additional tips for grape growers. They also offer advice for harvesting a crop of healthy and delicious fruit.

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Fertilization and Disease Management

Fertilizer applications are ideally based on the results of a soil test. If soil test results are not available, there are general rules of thumb you can follow:

• Apply slow-release 10-10-10 around the plants in the late spring, or use composted manures.

• Spread the fertilizer evenly over the bed, keeping it away from the trunk.

• Do not apply nitrogen in the late summer or fall.

In most areas of the country it's not possible to grow high-quality grapes without a spray program. Check with your local extension agent to get a recommended spray program for grape-growing in your area. You may also want to investigate some of the new biological fungicides that are on the market.

Harvesting

How do you know when it's time to harvest grapes? You can't go by color alone: grapes change to their final color before they're mature. A taste test is the best way to tell whether grapes are ripe. Grapes don't ripen after picking, so make sure they're fully ripe before you harvest them.

If you plan to make wine with your grapes, the best way to determine whether they're ready to harvest is to use a refractometer (figure A), which tests the sugars and acids of the grapes. To use this device, generally all you have to do is open the door in the top, pick a grape (typically in the middle of the cluster) and squeeze some of the juice on the top of the window frame (figure B). Close the top of refractometer; then look at the scale, which shows the total sugar in the grape (figure C). For wine-making, the grapes should have between 18 percent and 22 percent sugar.

Figure A

Figure B

Figure C

Figure D

Typically, you harvest a whole cluster of ripe grapes at one time. You can use a regular pair of shears, or you can use special shears with an extra-long nose; the nose helps you reach into the top of the stem of the grapes without damaging the clusters (figure D).

Note: On Fresh From the Orchard, grape grower Jack Mandula was shown harvesting a grape called Chamboursin, which he made into a wine that's similar to merlot. He used about 16 pounds of grapes to make a gallon of wine.