Fertilize and Increase Watering as Grape Growth Appears

Q. I have a grape, with dark colored fruit, growing on my established trellis. It’s already pruned. What should I do to it now?

Fantasy table grape growing in Las Vegas.

A. Of course your grape plant will need water and fertilizer when it starts growing in March. I would apply the fertilizer the first week of March and begin watering weekly during February.

As new growth appears, you should already be watering once a week and have any fertilizer applied. to help push new growth.

Which fertilizer to use? Any fertilizer used for fruit trees will work. It’s applied where the water is delivered to the plant but at least 12 inches away from its trunk. I prefer using a rich compost as a fertilizer instead, but it must be watered beyond any surface mulch so it comes in contact with the moist soil underneath it.

Whether you apply compost or mineral fertilizers to help new grape growth push, do it just before new growth appears for best results.

Grapes grow better in the hot desert if there is “plant litter” (surface mulch) on top of the soil where they receive their water. This surface mulch of 3 to 4 inches deep helps keep the soil surrounding their roots moist and cool. Woodchips from landscape trees make an ideal surface mulch for grapes and fruit trees because they easily rot and decompose into the soil.

Wood, whether its from "forests" or urban forests is a valuable and rare commodity in the desert.

Here woodchips are being dropped at the Ahern Orchard in Las Vegas to be used for soil enhancement around fruit trees and grapes.

It’s helpful to determine if your grape should be “spur pruned” or “cane pruned”. Bunches of grapes are always produced along last year’s growth. The difference when pruning different types of grapes is where the fruit is produced along this new growth. Spur pruned grapes produce their bunches at the base of last year’s growth. Cane pruned grapes produce their bunches from buds further out from this. Buds that produce grape bunches further out, when spur pruned short, are void of grape bunches. Pay attention to your variety of grape and whether it prefers spur or cane pruning.

Grapes and fruit trees grow much better and with fewer problems when NOT grown in bare soil but the soil covered in woodchip mulch.

Simplest way is to delay pruning until you see grape bunches starting to form. I know it can be heart-wrenching, just like thinning peach trees, but removing extra bunches will make each of the berries in the grape clusters larger.

When it’s an unknown grape variety I’m not sure about, I look for old grape clusters, remnants, produced last season. (I will take a few shots of this and insert later. I dont have any shots of this yet.) These can be subtle differences and not obvious to the casual observer. Count back the number of bumps or “buds” where these remnants were attached to older growth. Do this in several locations and get an “average” distance from where it grew. This tells you where you can safely prune last years growth and how much can be removed. Doing this can insinuate if a grape should be spur pruned or cane pruned in the future.