What to plant this week in Wilmington, DE
Wilmington gardeners, you are officially in the thick of late spring heat as the threat of frost has faded by a week or two. With overnight lows hovering near 5°F only historically in March, your current focus shifts to maximizing growth before the mid-November freeze arrives.
The next 7 days
Wilmington, DEGrowing in Wilmington right now
- The Cape Fear River valley often creates localized microclimates where cold air settles; avoid planting frost-sensitive transplants like peppers until after April 15th despite the 'sow now' options for hardy beans. Our sandy loam soils in New Castle County drain quickly, so ensure you amend planting holes with compost to retain moisture during our frequent afternoon thunderstorms.
- Rainfall is typically high right now, which can cause root rot in heavy clay pockets found in older neighborhoods; monitor drainage carefully when sowing Zucchini and Yellow Summer Squash directly into the ground. Watch for volunteer Seedlings from last year's Garlic harvest as the weather warms up, thinning them if they crowd your intended crops.
- Wilmington's humid summers encourage rapid fungal spread, so practice good air circulation in your rows of Melons and Watermelons to prevent powdery mildew before it becomes unmanageable.
Sow this week
2 crops- Yellow Summer Squash
- Zucchini
Transplant this week
Nothing is due to go out this week.
Harvest soon
36 crops- Basil
- Borage
- Bush Bean
- Cantaloupe
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Edamame
- Fennel
- Flour Corn
- French Marigold
- Garden Verbena
- Garlic
- Gourd (Ornamental/Bottle)
- Honeydew Melon
- Lima Bean
- Loofah (Luffa)
- Malabar Spinach
- Nasturtium
- Okra
- Pole Bean
- Pumpkin
- Roselle (Cranberry Hibiscus)
- Scarlet Runner Bean
- Shiso (Japanese Basil)
- Summer Savory
- Sunflower
- Sweet Corn
- Thai Basil
- Vinca (Madagascar Periwinkle)
- Watermelon
- Winter Squash
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Succession sow bush beans every two weeks to ensure a continuous harvest through late August.
- Thin seedlings early on okra and watermelon plants to allow remaining specimens room to spread their vines.
- Apply a light layer of compost around established summer squash and zucchini to feed heavy fruiting plants.
Pest & disease watch
- Watch for aphid colonies forming on the new growth of Okra and Bush Beans as temperatures climb into the 70s. Introduce beneficial ladybugs or spray with a strong jet of water if infestations appear.
- Cucumber Beetles are likely active now, targeting your Cucumber, Watermelon, and Squash plants; hand-pick adults in early morning when they are less active to reduce chemical reliance.
- Slugs thrive in our damp conditions and will feast on young Zinnias and Cleome seedlings; check under mulch and cardboard traps every evening after sunset.
Watering this week
Water deeply in the early morning to keep soil moist without wetting foliage, especially when fruit sets in.
Harvest zucchini and summer squash every two days to prevent them from becoming tough and bitter.
Wilmington gardening questions
3Can I still transplant Tomato or Pepper plants now, even though the list says 'transplant now' is empty?
Technically, you can move hardy seedlings like Bush Beans tonight since the ground temperature has warmed up above 50°F. However, for warm-weather crops like Tomatoes and Peppers, wait until after April 15th to avoid any late chill risk that could stunt their root systems.
My Cantaloupe and Watermelon plants are struggling; is the soil too wet or something else?
Check your drainage first, as Wilmington's frequent spring rains can suffocate roots in heavy clay spots. If the soil is soggy, gently pull back some mulch to let it dry out; if the soil drains well but leaves are yellowing, they may need more potassium-rich fertilizer.
When should I start thinking about planting Garlic for next fall's harvest?
You have time until mid-October to plant hardneck garlic varieties in our zone 7b climate, as dormancy needs cool soil temperatures. Aim to get them in by November 15th at the latest so they establish roots before the first hard freeze.
Other cities in zone 7b
12See the full zone 7b guide → · Plan your Wilmington garden in SproutGuide →