Planting calendar
May Planting Guide for Boston, MA: Raised Beds, Containers & In-Ground Gardens
In May, Boston gardeners can confidently plant warm-season vegetables and flowers outdoors as the risk of frost diminishes. This is an ideal time to transplant seedlings and sow heat-tolerant crops directly in raised beds, containers, or in-ground gardens for a productive summer harvest.
Plant now (quick list)
Tomatoes, Peppers, Cucumbers, Bush beans, Zucchini, Eggplants, Herbs (basil, parsley, dill), Marigolds
Plant now
- Tomatoes
- Peppers
- Cucumbers
- Bush beans
- Zucchini
- Eggplants
- Herbs (basil, parsley, dill)
- Marigolds
- Sunflowers
- Sweet potatoes (slips)
Start indoors
- Winter squash
- Pumpkins
- Melons
- Broccoli (for fall transplant)
- Cabbage (for fall transplant)
- Cauliflower (for fall transplant)
- Kale (for fall transplant)
- Brussels sprouts (for fall transplant)
Avoid
- Leafy greens (lettuce, spinach) in direct sun—heat sensitive
- Peas—best planted earlier in spring
- Potatoes—risk of late blight increases
- Root crops like carrots and parsnips—better planted earlier or later
- Tender annuals sensitive to sudden temperature swings
Next 2 weeks
- Harden off indoor seedlings before transplanting
- Mulch around plants to conserve moisture and suppress weeds
- Monitor for pests like aphids and flea beetles
- Water containers regularly as temperatures rise
- Stake or cage tall plants like tomatoes and peppers
- Continue sowing bush beans every 10–14 days for succession harvest
- Pinch back herbs to encourage bushier growth
FAQs
When is the last frost date in Boston for planting warm-season crops?
The last frost typically occurs in mid to late April, so May is safe for planting warm-season crops outdoors.
Can I plant tomatoes directly in the ground in May?
Yes, transplanting tomato seedlings outdoors in May is ideal after the frost risk has passed.
How often should I water container plants in May?
Containers may need daily watering as temperatures rise; check soil moisture frequently to avoid drying out.
Is it too late to start leafy greens in May?
Leafy greens prefer cooler weather, so May is generally too warm for direct sowing; consider shade or fall planting instead.
What are good companion plants for tomatoes in raised beds?
Basil, marigolds, and onions are excellent companions that can help deter pests and improve tomato growth.
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