Caging and Artificial Barriers: Cages can be constructed with PVC and fabric row covers. Brown paper or fine meshed bags can also be used. Non-porous bags are not recommended because they can lead to rot.
• When these methods are used it is required that either plants are hand-pollinated or pollinators must be introduced into the caged/bagged environment.
4. Time Isolation: You can plant different varieties of the same species in the same year as long as the times they flower do not overlap. For annuals, this could mean starting one variety early in the season and then starting another several weeks later. For biennials, you could have multiple varieties of the same species (such as onions) growing in the same place but only one that is in it’s second year and going to flower.