Hi Muhammad Wajid Raza, the general rule is apply moderate fertilizer prior to spring growth. If your credentials are correct and you currently live in Pakistan, that is the Northern hemisphere. So it maybe around April, the suggestion below is even earlier which wouldn't really hurt, but don't overdue it, small is better.

Fertilizer is N-P-K

You want a pretty high Nitrogen level at first it encourages leaf growth, leave it alone for a month. It is better to use manure rather than chemical type fertilizers.

Yeah, these are green ones I suspect you are talking red ones, didn't take the time to search for a good pic of red ones!

• Do a soil test:

The results of your soil test will tell you if you should be fertilizing your grapevines at all.

Grapevine Fertilizer: When And How To Fertilize Grapes

• When to Feed Grapevines

Grapes are deep rooted and, as such, require little additional grapevine fertilizer. Unless your soil is extremely poor, err on the side of caution and amend as little as possible. For all soils, fertilize lightly the second year of growth.

• How much plant food should I use for grapes?
• Apply no more than ¼ pound of 10-10-10 fertilizer in a circle around the plant, 4 feet away from each vine. In successive years, apply 1 pound about 8 feet from the base if the plants appear to lack vigor. Apply plant food for grapes just when the buds begin to emerge in the spring. Fertilizing too late in the season can cause overly extensive growth, which may leave the plants vulnerable to winter injury. Like almost every other plant, they need nitrogen, especially in the spring to jump start rapid growth. Use manure to feed your vines, apply it as early as January or February. Apply 5-10 pounds of manure, or 5-20 pounds of steer or cow manure per vine. Other nitrogen-rich grapevine fertilizers (such as urea, ammonium nitrate and ammonium sulfate) should be applied after the vine has blossomed or when grapes are about ¼ inch across. Apply ½ pound of ammonium sulfate, 3/8 pound ammonium nitrate or ¼ pound of urea per vine, this encourages fruiting. I would discourage using chemical type fertilizers but that option is up to you.
• Zinc is also beneficial to grapevines. It aids in many plant functions and a deficiency can lead to stunted shoots and leaves, resulting in a reduced yield. Apply zinc in the spring a week before the vines bloom or when they are in full bloom. Decreased shoot growth, chlorosis (yellowing) and summer burn usually mean a potassium deficiency. Apply potassium this really encourages fruiting. Use 3 pounds of potassium sulfate. This I can live with, it really, really helps.

Grapevine Fertilizer: When And How To Fertilize Grapes