How to Grow Shiraz Grapes

Test your soil's drainage by digging a hole, approximately one foot deep and filling it with water. Let it drain, then fill it again. If the soil is fully dry two days later, then the soil's drainage will be suitable for grapes, which need well-drained soil to grow properly and do poorly in wet conditions. The soil should remain unamended with no additives to change the grape's character.

Find a location that gets full sunlight. Warm climates with hot, dry summers are generally better for grapes, as too much moisture can be bad for the plants. Hillsides are a popular location for planting, particularly slopes facing towards the southeast or southwest, which receive the most sunlight. Flat land works too, as long as the grapes are not in the shade. The amount of sunlight the plant's leaves receive helps determine the quality of the grapes at harvest time.

Set up a three-wire trellis for a more orderly looking vineyard. Place an 8-foot long wooden post into the ground at the end of each row, with 6 feet of the post above ground. Hold the end posts steady with earth anchors. Sink more wooden posts, all of the same height, 24 feet apart from each other along the length of the row. Next, put steel fence posts into the ground at a distance of 8 feet apart, again at the same height. Hang a length of heavy-gauge wire about 60 inches above the ground. Another length of wire should be strung tightly across the posts at around 50 inches, and a third at around 40 inches above the ground.

Plant container-grown shiraz grapes at any time from spring to fall by digging a hole in the soil. The hole should be as deep as the container the grapes were grown in, or slightly deeper. Transfer the plant from the container into the hole. Space each vine about 6 feet apart, with rows about 8 feet wide. Tie a promising shoot from each vine to the wires with string for the first year and prune any other shoots growing from the roots.

Plant bare-root shiraz plants during the winter months when the vines will be dormant. Dig generous holes, though not so generous that the vines are unable to stand upright. Follow the same general procedure outlined above.

Provide grapes with plenty of water during their first few seasons.

Water grapes two to four times per week during the growing season after they are fully established.

Fertilize soil during the early spring and late fall, depending on local soil conditions.

Test fruit regularly to determine the best time to harvest. Ripe grapes will have a whitish bloom on the skin and are sweeter than unripened grapes. The precise time to harvest shiraz grapes is subjective, as different levels of ripeness can affect the character of wine made from the grapes.

Store grapes at 32 degrees Fahrenheit. The relative humidity should ideally be around 85 percent.