What Seeds Should I Plant in April?

Annual and Biennial Seeds Outdoors

• Plant seeds of cabbages, root vegetables, leafy greens, parsley and chervil directly where they will grow as soon as nighttime temperatures in your area are reliably above freezing. Space seeds twice as close as the spacing recommended on the seed packets, and thin to final spacing once the seedlings have emerged. This ensures you end up with as many plants as you intend even if some of the seeds do not germinate.

Annual Seeds Indoors

• Plant tomatoes, cucumbers, corn, summer and winter squashes, peppers, okra, beans, eggplant, basil and cilantro indoors in April if outdoor nighttime temperatures in your area are still below 50 F. Plant in potting mix in flats or small pots. Lightly water the soil after planting the seeds. Cover the flats or pots with loosely tented plastic bags to keep the soil moist. Remove the plastic bags as soon as the seeds germinate. Keep these seedlings indoors until nighttime temperatures are above 50 F.

Perennial Seeds Indoors

• Plant perennial herbs and flowering ornamental plants from seed indoors in April. Most perennials including herbs with woody stems such as rosemary and sage grow slowly and their seeds take weeks to germinate. Their seeds require constant moisture and warmth to germinate. Starting perennial plants from seed indoors makes it easier to maintain that moisture and warmth and to monitor the plants' growth until they are ready to transplant.

Transplanting

• Transplant annual and biennial seedlings planted indoors when they have three sets of leaves and nighttime temperatures in your area are above 50 F. Transplant seedlings from perennial herbs and flowering ornamental plants once they have reached a height of at least 3 inches and nighttime temperatures are above 45 F. Before transplanting, place the seedlings in their original planting flats or small pots outside in a partially shaded area for several days to acclimate them to fluctuating outdoor temperatures. Be sure to water regularly during this hardening off period.