What to plant this week in Hamilton, ON
Hamilton gardeners are now in full swing with late frost risks fading by April 21, allowing immediate harvests of mature tomatoes, peppers, and root crops while warm-season seeds like cucumbers and okra go directly into the soil. The city's tight urban valley traps cold air overnight, so protect tender transplants from sudden dips below -5°F even as summer heat builds.
The next 7 days
Hamilton, ONGrowing in Hamilton right now
- Avoid planting frost-tender seeds indoors this week; focus exclusively on direct sowing warm-season crops like bush beans and yellow squash that thrive in our clay-heavy soils.
- Use raised beds or mulch heavily to combat Hamilton's notorious 'cold air sink' effect where frost settles deep in the valley bottoms after April 21.
- Monitor moisture closely as the region transitions from spring showers to summer drought patterns, ensuring consistent watering for newly sown zinnias and sunflowers.
Sow this week
17 crops- Basil
- Borage
- Bush Bean
- Cleome (Spider Flower)
- Cucumber
- French Marigold
- Malabar Spinach
- Nasturtium
- Okra
- Pole Bean
- Scarlet Runner Bean
- Summer Savory
- Thai Basil
- Vinca (Madagascar Periwinkle)
- Yellow Summer Squash
- Zinnia
- Zucchini
Transplant this week
Nothing is due to go out this week.
Harvest soon
58 crops- Anaheim (New Mexico) Pepper
- Banana Pepper
- Basil
- Beefsteak Tomato
- Beet
- Bell Pepper
- Borage
- Brussels Sprouts
- Bush Bean
- Cantaloupe
- Carrot
- Cayenne Pepper
- Cleome (Spider Flower)
- Cosmos
- Cowpea (Black-Eyed Pea)
- Cucumber
- Dahlia
- Edamame
- Eggplant
- Fennel
- Flour Corn
- French Marigold
- Garden Geranium (Zonal)
- Garden Verbena
- Garlic
- Honeydew Melon
- Jalapeño
- Lantana
- Lima Bean
- Malabar Spinach
- Marconi Pepper
- Nasturtium
- Okra
- Ornamental Sweet Potato Vine
- Parsley
- Parsnip
- Petunia
- Poblano Pepper
- Pole Bean
- Potato
- Roma Tomato
- Rutabaga
- Scallion (Bunching Onion)
- Scarlet Runner Bean
- Serrano Pepper
- Shiso (Japanese Basil)
- Snapdragon
- Summer Savory
- Sunflower
- Sweet Corn
- Thai Basil
- Tomatillo
- Tomato
- Vinca (Madagascar Periwinkle)
- Watermelon
- Yellow Summer Squash
- Zinnia
- Zucchini
Seasonal tips
- Succession sow bush beans and pole beans every two weeks for a continuous harvest throughout the summer.
- Mulch around young tomato and pepper plants to retain soil moisture as temperatures rise above 80°F.
- Thin carrot and beet seedlings now to prevent overcrowding and ensure sturdy root development.
Pest & disease watch
- Watch for early aphid colonies on newly sprouting bean varieties like Scarlet Runner Beans as temperatures climb above 60°F.
- Scout cucumber plants for downy mildew spots, which spread rapidly in Hamilton's humid valley summers when foliage is wet overnight.
- Check tomato vines and pepper plants (Anaheim, Jalapeño) for spider mites before they establish in the protected microclimates of local backyards.
Watering this week
Water deeply in the early morning to encourage deep root growth and reduce evaporation losses during this hot season.
Harvest sweet corn when the kernels are milky and firm, not yet hard or fully browned, for peak sweetness.
Hamilton gardening questions
3Can I plant my basil seeds now or should I wait until after April 21?
Since your average last frost date is April 21 and soil warmth is critical, sow Basil directly outdoors this week rather than waiting for transplants. The listed 'sow_now' varieties like Thai Basil handle our local humidity better when started in situ.
My tomatoes are heavy with fruit but the nights are still chilly; will they ripen?
Harvest your Beefsteak and Roma tomatoes now before night temperatures drop below freezing, as the plants may struggle to ripen remaining green fruit if frost hits unexpectedly. Protect any unripe peppers like Cayenne or Poblano varieties with row covers until after April 21 stabilizes.
Why are my Zucchini plants showing yellow leaves and stunted growth despite regular watering?
Hamilton's clay soils often retain excess moisture that causes root rot in squash, so check drainage around the base of your Yellow Summer Squash and Zucchini. Reduce watering frequency slightly to let the soil surface dry between sessions, which mimics our typical summer rainfall gaps.
Other cities in zone 6b
12See the full zone 6b guide → · Plan your Hamilton garden in SproutGuide →