What to do this week

It has been cool but very dry across much of the DMV for the past month. This time of year, plants are mature and have a lot of leaf area for evaporation, so they can struggle even though it is not blazingly hot. Be sure to water regularly, especially plants in containers that may need daily watering. 

Cover crops are single species or plant mixes designed to cover a planting area to prevent weed invasion and improve soil conditions. Winter cover crops are sown by seed in late summer to sprout quickly and last into the cold season. Some winter cover crops are intended to survive cold temperatures and then be tilled into the soil in the spring. For no-till options, select a cover crop that will be killed off by cold temperatures in mid-winter. Instead of purchasing expensive seeds in small quantities, cover crops are often sold in bulk at low prices as special mixes. 

Some options for cover crops that will winter kill in a cold snap or in colder regions of the DMV include

forage radish (daikon types)

oats 

some brassicas

field peas

Forage or tillage radishes are used to break up compacted soils. The radishes will die and then rot in mid-winter, returning nitrogen into the soil.

If you select a cover crop that does not winter kill, be sure not to choose an aggressive species that will be difficult to cull in spring unless you are looking for a crop that will continue into the following summer.

Early September is the time to plant cool weather fall crops such as:

lettuce

kale 

cold hardy asian greens

fava beans

radishes

spinach

turnips

kohlrabi

Because insects are out in force in the late season, brassicas will need protection from cabbage worms - Bt, spinosad, or fine netting are all helpful. If you wish to extend the season, start planning a way to use hoops/covers, cold frames, or similar. The above photo was taken in February of tatsoi doing just fine under a heavy polyspun cover.