This is the best of the month for evaluating the success of your Harlem garden. Try to assess the productivity of your crops in relation to your personal needs.
Next year you may want to plant more Lettuce and fewer Tomatoes or try new varieties for a more abundant crop. Take photographs of your garden now so you have a record of your garden’s plants.
Watering. There still may be quite a few hot dry days left in September, so be sure not to neglect your watering. Be particularly attentive of newly planted greenery and seeded lawns.
Weeds. Eradicate all weeds from your garden now before they go to seed. If you are using the manual method, take care to remove the taproot along with the top of the plant.
Cover Crops. These will be very helpful during the winter as they will protect the soil, acting as a living mulch, in addition to being a great fertilizer when being turned under in the spring. You can plant your cover crop seeds in the vegetable garden even before you pull out your produce. Clear the summer debris from your garden. In the remaining bare spots plant your cover (green manure) crops such as Winter Rye, Lambs Quarters, Vetch, Soy Beans, etc., as early as possible.
Compost. Keep your pile watered. Start collecting organic material for winter sheet composting. Leaves may start to fall now, so gather them to add to your present pile or start a separate pile for leaf mold.
Lawn. Continue cutting the Grass as long as it continues to grow vigorously. You may start a new lawn until the end of September, but remember to keep the seeded areas moist and untrampled. When planting a new lawn, consider seeding a mixture of Grass and Clover. The Clover will fertilize the grass, due to its nitrogen-fixing bacteria. Add bone meal and wood ash to established lawns. Also, when planting a new lawn, add a lot of organic matter to the soil, the Grass will appreciate it. Grass prefers good soil to a depth of 24”.
Bulbs. Order your bulbs and necessary supplies now (soil additives, bulb planters, etc.) Plan and prepare your beds and layout. Lilies-of-the-Valley, Scilla, Daffodils, Snowdrops, and members of the Narcissi family may be planted at the end of September.
Tender Bulbs. Harvest gladioli as soon as the foliage turns brown. Before the first light frost, take up Tuberous Begonias with clump of soil and put in cool, dark place. When foliage dries cut tuber loose from the excess soil and place in dry sand at 50 degrees temperature.
Propagation. Collect annual and perennial seeds now for planting next spring. Do not, however, rely on these alone for your next year’s crops. After Delphinium and Hollyhock have withered, leave the seeds of a few good specimens on the stalk until ripe. Harvest the seed and replant immediately. Try sowing Larkspur, Poppy, Sweet Alyssum, Ageratum, Calliopsis, Cornflower, Petunia, Pansy, and Cosmos now. They may survive the winter with a heavy mulch of straw or excelsior. You may still try sowing some of the cool weather crops that have a relatively short number of days until harvest. Keep Chrysanthemums well watered and fed with manure tea until the buds are almost open to avoid woody stalks and poor flowering. Dig up a large root of Bleeding Heart, Anchusa or Oriental Poppy and cut the roots into pieces and plant in moist sandy loam. Divide Iris, divide Wild Aster (Michaelmas Daisies), leaving 4 to 5 stalks per plant. Tag Phlox for later division. September 15th is last safe date for transplanting Peonies.
Do not feed your roses any longer, but continue to keep them well watered and mulched. Prepare rose bed for planting later in the fall.
Tree and Shrub. They should be planted early enough to allow roots to establish themselves before heavy frost, otherwise the plant material is only “heeled in” and subject to winter kill. Stop fertilizing established trees or shrubs as this may stimulate new growth and delay the natural dormancy of the tree or shrub. Complete the pruning of all but spring flowering shrubs. As soon as the foliage turns, it is time to transplant. New stock should be firmly staked and watered. Delay planting Magnolias, Dogwoods and Birches until the spring. Azaleas may be planted any time from now until late spring. Place your order for fruit trees and prepare the planting holes before their arrival. Evergreens are entering their most dormant period, so you may transplant them now. Bagworms should be removed at once and discarded.
Indoors. At the end of September, start bring your houseplants indoors from the terrace or garden gradually while the weather is still warm enough to leave the windows open. This will allow your plants to adjust gradually to the drier air indoors and lessen shock. Obtain your soil for winter potting. Take cuttings from Coleus or any other plant you may wish to root indoors before the first frost. Cut Strawflowers and seed pods for dried flower arrangements. Collect Clorox bottles, bushel baskets as cloche or hot cap materials to ward off the first frost and extend your growing season.
Preparing Beds. A fairly effortless way to prepare new beds in a grassy, weedy area is to lay out the borders, cover the area with newspapers, old carpeting, bits of linoleum, old plywood and weight the covering down with rocks or bricks. Within six weeks all stalks and roots should be dead and can be turned under. Test the soil, add appropriate soil conditioners, and behold — a new bed.