Originating from the Mediterranean, Brussels sprouts are a slow-growing but very bountiful crop. Planting Brussels sprouts from seed outdoors requires a very long, cool growing season. Timing is important when growing Brussels sprouts. In most regions, it is best to plant Brussels sprouts so that they come to harvest in autumn. Start seeds indoors 12 to 14 weeks before the first frost in autumn for harvest after the first frost. Brussels sprouts reach maturity 80 to 90 days after transplanting and 100 to 110 days after sowing seed depending on the variety. Time planting so that Brussels do not grow in periods of extended warm weather much above 21 C.
Brussels sprouts grow best in fertile compost-rich, well-drained soil. Add 15cm of more of aged compost or commercial organic planting mix to planting beds before planting then turn the soil to 30cm deep. A heavy soil, not a light sandy soil, is best for growing Brussels sprouts. Brussels sprouts prefer a soil pH between 6.0 and 6.8. If clubroot disease has been a problem in the past, add lime to adjust the soil to 7.0 or slightly higher. Avoid planting Brussels sprouts in the same location two years in a row.
Crop rotation is important to prevent soil nutrient depletion and soilborne diseases.
Giving Brussel sprouts a generous amount of room to grow will give a larger harvest and larger florets.
Start seeds indoors about 8-12 weeks before outdoor planting. Days to harvest are from the transplant date.
Sow seeds 5 mm deep in seed-starting formula.
Keep the soil moist at 21 C
Seedlings emerge in 10-21 days
Once planted in the garden use a row cover to prevent the cabbage moth.