To achieve proper cross-pollination of Gala and Golden Delicious apples, choose a pollinator that blooms at the same time. Since Gala and Golden Delicious apple trees bloom at the same time, you can plant one of each and allow the trees to cross-pollinate one another. Red Delicious and Winter Banana apple flower at the same time as both Gala and Golden Delicious apples.
Apple pollen is carried from one tree to another mainly by bees. Avoid spraying insecticides or other chemicals while bees are present during the flowering period. Wait until the bees have finished their work so the Gala and Golden Delicious trees' flowers receive enough pollen transfer to ensure good fruit production.
Plant pollinator trees 50 feet from the Gala or Golden Delicious tree but no more than 100 feet away. This allows the bees to visit each tree more frequently during the blooming period. If the trees are too far from one another, the bees may detour to closer blooms, and cross-pollination -- and subsequent fruiting -- will be reduced.
Crabapples generally bloom slightly earlier than apple trees, but there is enough overlap for good pollination. Any variety of flowering crabapple tree will provide adequate cross-pollination for either Gala or Golden Delicious apple trees. Snowdrift crabapple blooms slightly later than Gala or Golden Delicious, but its flowering period overlaps and extends beyond that of both apple varieties.
Avoid planting triploid varieties, as these apple trees are sterile and cannot cross-pollinate your Gala or Golden Delicious apple trees. Triploid varieties include Winesap, Jonagold, Stayman and Mutsu.
If you have a single Gala or Golden Delicious apple tree and don't have room to plant a crabapple or apple tree close enough for pollination, cut some flowering branches off the other apple tree or crabapple, place the cuttings in buckets of water, and hang the buckets in the apple tree you need pollinated. The wind and the bees will take care of the rest.