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From The Professor's Greenhouse: September, (Part 1) Interplanting

Season-relevant tips on planting, growing, and maintaining thriving gardens and landscapes from Professor Kevin Jones, Botanist & Biology Professor at Charleston Southern University.

No spring nor summer’s grace

Hath such grace

As I have seen in one Autumnal face….

John Donne

Blurring Lines

Interplanting is a term I use for putting veggies and ornamentals together. I have a small suburban yard, and as such, I have limited space for all the plants I want – so many plants, so little space.

Putting veggies among the ornamentals maximizes the productivity and beauty of the space available. I see grass and bare earth as blank places to grow something else.Some of the ways I hedge my bet is by putting the peppers next to the coreopsis. And there is squash on the border by the drive. Garlic goes where I have a few inches. Salad greens go among the peppers that are over daffodil bulbs. I have sweet potatoes acting as a ground cover in the front yard and Irish potatoes between the roses, and a large potted plumeria. There are a few eggplants around the lemon grass by the rudbeckia. There are herbs scattered everywhere. I have an edge of a walkway planted with beets – I think they are a beautiful plant. I hate eating them, but Anne loves them.

Sweet potatoes, interplanting
Sweet potato vines as ground cover. PC: Kevin Jones

Our house faces west, and the drive is on the north, so the south side is the unused side yard. We built a trellis for grapes along that wall, and this year we planted honeydew melons under the grape trellis. The melons were delicious. Next year I am adding raised beds on that side; the grass is merely a place keeper until I do.

Grape vine trellis. PC: Kevin Jones

Our next-door neighbors have a backyard dedicated to Diablo, an English bulldog that barks like it will eat you but is a puppy at heart. We have a pumpkin planted on the fence between us.

5 year old Habanero Pepper plant, pruned Bonsai-style. PC: Kevin Jones

Another way I blur the line between veggies and ornamentals is by using them as potted plants. I have a Habanero Pepper that is over five years old planted as a bonsai specimen. True, I cannot eat Habaneros, but they are beautiful golden berries on the plant, and my neighbor loves them—the same with Thai hot peppers and bird’s eye chili peppers.

There is a large pot of ginger in the yard that is harvested in the fall, with some replanted to spend the winter in the greenhouse. A word on ginger: it is easily started from the ‘hands’ available in the produce section at the grocery store. Press them into damp soil. They will lose their leaves as cold weather approaches, but with warm weather, they leaf out nicely. I have only recently read that they will survive under a thick mulch here and will let you know in the spring. Until then, plant in a pot and bring it into a cool, dry garage for the winter.

Ginger plant
Culinary ginger started 15 years ago. PC: Kevin Jones

With such limited space, we have some dwarf fruit trees in tubs and planted carrots, radishes, and beets around the base.

A Salad Bar

I have an area in the flower border where I was not sure what I wanted to be a permanent resident. There are daffodil bulbs resting under the soil for a spring display, but it looked rather bare after mid-May, so I planted peppers in the open area over them. When the peppers leave, I will again have a bare spot, and peppers are an excellent companion crop to lettuce, so I am planting a salad greens bed now to enjoy tender green leaves through the cooler months. True, I do give them a little protection on the few hard freeze nights.

I plant a bed of salad greens in the fall to enjoy tender young greens of lettuce, mustard, spinach, arugula, and mizuna through the cooler months and into mid-spring. As I am growing them for their tender young leaves, I do not worry too much about spacing, and, as they will be growing after the peppers have faded, I get double (triple) use of the space.

The process is easy:

Prepare the soil. I sprinkle an all-purpose granular fertilizer around the peppers and lightly rake it in, staying shallow to avoid the pepper plant roots. I then rake the soil smooth.

Sow a mixture of different salad greens on the surface. I am not growing them for the roots or heads, so sow closer together than the packet directions say. I use a mixture of different kinds and colors of lettuce, mustard, mizuna, spinach, and beets.

Gently press the seeds into the soil and keep the surface moist until after germination and the initial growth; drying will kill the germinating seeds.

I begin harvesting as needed after only a few weeks. To harvest, I shear the amount of leaves I need from an area of plants about two inches from the ground. The trick is to remove leaves but leave the growing points intact.

When the peppers die, I will cut them off at the ground instead of pulling them out, and when the hot weather hits next year and the greens are no longer producing or have gotten bitter, I will turn them under, being careful to avoid the daffodils.

Tender salad green shoots planted in the fall
Salad greens make a great companion crop for peppers in the fall. PC: Kevin Jones

Veggie September Chores (Ornamental Chores are in Part II)

1. Garlic, onions, and shallots can be set out in September and into October. Space 4ish inches apart and 3 inches deep in an exposure that will get lots of sun. Consider putting them in ornamental beds as leaves that emerge will stay green through winter. Soft neck garlic does best in our area.

2. Cilantro, caraway, dill, and chervil are biennials and should be started now for winter and spring leaves. They have carrot-like roots and do not transplant well, so the seeds should be sown directly in the soil.

3. Parsley, sage, rosemary, and thyme (also oregano) can be planted this month. Parsley is a biennial, but the rest are perennial and will happily go through winter and be providing leaves by spring.

4. Parsley, dill, fennel, and to some extent, carrots are host plants for the green, black, and yellow-striped caterpillars of the eastern black swallowtail butterfly. Yeah, they can devastate the plant in short order, but the butterfly brings such joy, and the plants will grow new leaves. Just plant some extra and share.

5. Beets, cabbage, and collards should be planted by mid-September.

6. Set out or sow seeds of vegetables for the fall or winter: lettuce, turnips, mustard, spinach radish, carrots. It is important to prevent the surface of the soil from drying as seeds germinate. Be sure to label them with the variety. I always tell myself I will remember, but I never do. Miss Karen can fix you up with seeds, fall crop transplants, and labels.

7. This is a good time to plant strawberries. Full sun, well-drained, and fertile soil. Add compost.

8. Continue harvesting summer vegetables to prolong production.

9. As fall progresses and the garden space is cleaned from the summer crops, consider a mulch of leaves or straw. Mulch will keep cool-season weeds from germinating, and over the winter, this will break down and be easily turned into the soil in spring. Or plant a cover crop. Both of these will prevent cool-season weeds from germinating, prevent erosion and soil compaction, and add organic material to the soil. And both look better than bare soil.

10. Keep a lookout for pests in the vegetable garden (and ornamentals); as the weather cools, some make a strong second showing. (Hey, bean beetles – I’m looking at you.) To control pests in the garden, see Miss Karen at Santee Hardware for a variety of food-crop safe options. Some of my favorites for their effectiveness, safety, and relatively low environmental impact are 1) neem oil, an all purpose, organic 3-in-1 product that can be used in growing and dormant periods

2) Bt spray, a selective, natural growing season insecticide that targets worms and catepillars but will not harm birds, earthworms or beneficial insects and can be used up until the day of harvest.

3) insecticidal soap, an organic gardening-compliant option that targets soft-bodied insects on a wide variety of plants.

An off-label hack: use Formula 409 household cleaner! It kills bugs, such as aphids, that it contacts by destroying their waxy covering.

Keep your eyes open for the first deliveries of fall vegetables from Bonnie plants, and fall-planting seeds and bulbs from Hudson Valley Seed Co. coming soon!


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