Gardeners Checklist: Here Is What to Do on the Week of Sept. 11

By Ron Kujawski

• Buy some colorful hardy mums for planting in spots in flower beds vacated by spent annuals. Mums are also great for flower boxes and patio pots. While mums planted in the ground should survive the winter if mulched, those in containers will not be so lucky. The small, button-type mums are reputed to be the hardiest. When mulching mums in late fall, use a light, airy mulch such as straw or pine boughs.

• Make a sketch of the vegetable garden. It doesn’t have to be a van Gogh since all you want to do is record where specific crops were planted this year. Next year, each crop should be planted in a different location. This is called crop rotation, and its purpose is to prevent the buildup of certain plant disease and pest problems.

• Try one more sowing of seeds of spinach, leaf lettuce, mache, arugula, and radishes. These seeds should sprout quickly since soils are warm, and the resulting plants will continue to grow well even as air temperatures steadily cool down through fall.

• Be alert for frosts. There does not appear to be any in the near forecast, and it’s been several years since we’ve experienced a September frost in our garden, but it seldom pays to tempt fate. Move potted plants indoors if you haven’t already done so, and be prepared to cover tender plants if a frost is predicted.

• Leave Thanksgiving and Christmas cactus outdoors a little longer, as long as they are not exposed to frosts. Cool temperatures actually stimulate flowering of these plants.

• Stop watering amaryllis and place the plants in a cool (50 degrees F) location for about 10 weeks. Cut off the leaves once they have dried up. After 10 weeks, move bulbs to a warmer spot and begin watering again to promote flowering.

•Collect soil samples from lawns and gardens for testing. It’s a good idea to test soils every three to five years, especially if plant growth has been less than satisfactory. For information on collecting and mailing in soil samples, go HERE.

•••

September is a month of transition. For example, we transish (a new verb I nominate for addition to the Oxford English Dictionary) from T-shirts to sweat shirts, from relaxed vacation mood to frenzied disposition, and from salads to soups and stews. There’s also a transition going on in gardens. Perennial plants respond to shorter days and cooler nights by shifting their focus from shoot growth to new root growth. This is why you see so many nurseries and retail garden centers promoting fall planting of trees, shrubs and herbaceous perennials. The success of planting is largely dependent on the successful establishment of a strong root system. With soils still quite warm and moist, and plants moving food in the form of starch from their shoots to their roots, good root development is pretty much guaranteed. So, go ahead with fall planting, but be sure to water new plantings should Mother Nature turn off the faucet, something she has thus far been reluctant to do.

Ron Kujawski began gardening at an early age on his family's onion farm in upstate New York. Although now retired, he spent most of his career teaching at the UMass Extension Service. He serves on Berkshire Botanical Garden’s Horticulture Advisory Committee. His book, Week-by-Week Vegetable Gardener’s Handbook, is available here.