What to plant this week in Sioux Falls, SD
Sioux Falls gardeners are currently in the critical transition window between spring cleanup and summer planting, with the average last frost date of May 8 marking the official start for your warm-weather crops. While mid-May temperatures can still dip into the teens overnight, it is safe to move out those heat-loving giants like melons and peppers that have been waiting all winter.
The next 7 days
Sioux Falls, SDGrowing in Sioux Falls right now
- Sioux Falls' heavy clay soil retains moisture well but drains slowly; amend raised beds with compost now to improve aeration before transplanting water-intensive crops like pumpkins and squash.
- The city's tendency for sudden, severe wind storms in May can easily snap young stems; use sturdy tomato cages immediately when setting out tomatoes, peppers, and eggplants.
- Take advantage of the short window before soil heat drops off by sowing quick-maturing bush beans and zucchini directly into the ground, as these varieties need consistent warmth to establish roots.
Sow this week
No direct sowing windows open this week.
Transplant this week
Nothing is due to go out this week.
Harvest soon
44 crops- Basil
- Borage
- Brussels Sprouts
- Bush Bean
- Cantaloupe
- Celery
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Fennel
- Flour Corn
- French Marigold
- Garden Verbena
- Garlic
- Ghost Pepper (Bhut Jolokia)
- Gourd (Ornamental/Bottle)
- Habanero Pepper
- Honeydew Melon
- Leek
- Lima Bean
- Lisianthus (Prairie Gentian)
- Loofah (Luffa)
- Nasturtium
- Ornamental Sweet Potato Vine
- Parsnip
- Pole Bean
- Potato
- 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
- Focus on soil preparation now by adding compost and organic matter to improve drainage before spring thaw.
- Clean up garden debris and remove winter weeds that may have survived under snow cover.
- Plan your succession planting schedule based on the May 8th last frost date for warm-weather crops.
Pest & disease watch
- Watch for early aphid colonies forming on newly emerged seedlings; a strong water spray or insecticidal soap is often enough for control at this stage.
- Slugs and snails are still active in cooler, damp May nights and will target tender lettuce and brassicas before they harden off.
- Monitor for cucumber beetles as soon as cucumbers and melons sprout, as these pests can devastate plants quickly once flowering begins.
Watering this week
Skip outdoor watering entirely until the ground thaws, but ensure storage areas stay dry.
Use this quiet time to order seeds for your summer crops like Watermelon, Zucchini, and Sunflower so they arrive by late winter.
Sioux Falls gardening questions
3Can I plant my watermelon seeds now in Sioux Falls?
Yes, with the frost average ending May 8, the soil is finally warm enough to start those cantaloupes and honeydew melons directly in your garden. However, ensure you wait until all danger of a hard freeze has passed completely before sticking those heat-loving seeds into the ground.
My garlic bulbs are ready for planting now, but my soil looks heavy and wet.
If your clay-heavy Sioux Falls soil is still soggy, hold off on planting garlic until it can be worked without forming large clods; forcing it in when too wet will cause the cloves to rot before sprouting. Wait a day or two for drainage if possible, then place the bulbs 2 inches deep with the pointy end up.
What should I do about those black spots on my basil leaves?
Those are likely early signs of downy mildew or fungal issues common in our humid springs; remove any affected leaves immediately and space your plants wider to improve airflow. Avoid wetting the foliage when you water, as this spreads the spores faster in Sioux Falls' climate.
Other cities in zone 5a
6See the full zone 5a guide → · Plan your Sioux Falls garden in SproutGuide →