The bees have no shortage of food. There are plants and trees in bloom all over the place. Having plenty of food for the bees from early spring through fall is very helpful for growing crops which need pollinating. You can’t just put out a “help wanted” sign and expect the bees to arrive. They need to be fed all season long. They can’t hang out in their dens waiting for your crops to bloom. They have their lives to live. Have plenty of flowers all the time, and you can guarantee a healthy population of bees to pollinate your crops.