Many producers will likely have their alfalfa seedings planted in the spring due to their agronomic crop rotation. However, there are excellent opportunities for alfalfa to be planted in the summer after wheat, oats or barley are harvested or when a field has been fallow often due to delayed planting following wet conditions earlier in the spring (obviously not this year). Michigan State University Extension recommends most forage legumes should be planted by August 1 in northern regions and August 15 in southern regions. If you are considering planting alfalfa you might ask, “What are the advantages or disadvantages of planting alfalfa during the summer?”
Summer seeding advantages:
- The number one reason why summer seedings can sometimes be more successful is that weeds are less likely to compete for needed water and soil nutrients. Weeds that might be present can be controlled prior to establishment by either a herbicide application or tillage. The need for a herbicide application (non-glyphosate resistant) following planting is reduced since most broadleaf weeds normally emerge in the spring.
- Summer seedings planted early enough in the summer/fall will be in full production for the coming growing season. When you compare the tonnage of alfalfa in a seeding year compared to the first full growing season, this can provide added income.
- Summer seedings usually have warmer, drier soil conditions and are less likely to have seedling diseases such as Pythium, Aphanomyces and Phytophthora root rot. Seedling diseases are more likely during the spring when soils are normally cooler and wetter.
Summer seeding disadvantages:
- Summer seedings are planted when moisture can be limited. In the event that a rain occurs to germinate the seed followed by hot and dry weather, seedings can be left in dry soil, wilt and die, resulting in a crop failure.
- If the seeding is planted into dry soils and no rain occurs, the seed will wait for a rain event before germinating. Delayed emergence may make the seeding susceptible to winter kill if the plants do not have enough growth to store adequate carbohydrates in the roots.