Cauliflower and Broccoli Seedlings.

Asked January 30, 2015, 12:10 PM EST

We plant our cauliflower and broccoli seed in plug trays for later transplanting. I use a commercial seedling mix. I "water in" the mix with a solution of 4-15-12 fertilizer at the prescribed rate. I get a high germination rate that is even across the tray, and from tray to tray. The problem I have is getting a consistently strong plant for transplanting. Within the same tray, I have a mix of strong plants and very spindly, weak plants. Is there anything that can be done that will result in a higher rate of strong, transplantable seedling?

Marion County Oregon

3 Responses

Good morning,
Can you tell me a little more about your growing system? Are they in a greenhouse, hoophouse or other? Do you use lights or rely on sunlight?
Ed Peachey
Hort Dept OSU

Thank you Ed for your response. I plant the seed in plug trays, and place the trays on heat mats (72deg.F)

Germination begins in about 4 days, and is fairly complete at 7 days. I get an excellent germination rate, at nearly 100%. They remain in my kitchen which has an east and south exposure window until day 7. At day 7, I take the trays to our unheated green house (I do have heat in the event of a freeze, but do not use it otherwise). I do not use artificial light. I continue to use the 4-15-12 liquid fertilizer through week 3, and then switch over to an 8-16-8 formula.

The most common reason for spindly brassica plants is low light intensity and warm growing conditions. I am not sure where your greenhouse is situated, or how much light the seedlings receive. is it in a shady area? I suggest you augment with a fluorescent light, usually placed a foot or so above the seedlings. You could also set them out in direct-sunlight during the day. Wind and direct sunlight will make your spindly plants more rugged.