Leggy Broccoli Seedlings

13 years ago

I transplanted my broccoli seedlings into styrofoam cups today. I know, not a green product, but it was all I had on hand at the time. However, they are very leggy even tho I've been growing them about 2-3" from the light. They are a bright green at least - no yellowing or pale foliage.

I've been reading on the Internet that I should maybe have buried the stems deeper, like tomatos (caveat is that tomatos have adventitious roots and I don't think broccoli does), and want to make sure that is okay. I have enough room in the top of the cup to add more soil if necessary.

It seems broccoli seedling may have a tendency to be somewhat leggy. I have my ceiling fan on so they get air movement and in all other ways they seem healthy.

Susan

Featured Answer

Okiedawn OK Zone 7

13 years ago

Broccoli seedlings get leggy when they are grown at temperatures warmer than what is ideal for them and/or when grown too far from the lights or a combination of both. They have a tendency to get leggy because most humans grow them at an indoor temperature that feels good to us humans but which feels hot to the cole crops.

While most seedlings grow fine at 60 to 65 degrees, I've found broccoli does better if grown at 50-55 degrees.

Since my seed-starting room stays warmer than that, I move broccoli outside the day it pops up out of the soil-less mix, and then move it back indoors at night. Keeping it outside in generally cooler temperatures (well, except for this year when it has gotten too hot too early ) helps prevent the legginess. Also, having the light 2 to 3" away encourages legginess. I keep the lights so close to the plants that you can't stick your finger between the light and the tallest plant, so maybe 1/4" away or less. That helps keep down the legginess too.

You can repot them deeper and they'll be fine, but do try to get them cooler air or they'll keep growing too fast and stretching because of the "heat". To a lesser extent cauliflower is the same way and so is cabbage, although it seems to me that cabbage doesn't stretch as much as broccoli does under identical conditions.

I don't start many non-cole crops in the same flat as broccoli because of the cole crops' need for cooler temps, but lettuce likes the cooler temps too so I often seed them in the same flat as the broc.

I try to put broccoli plants in the ground when they have 3 to 5 leaves, which is about when they're 3 to 5" tall. If you hold them in containers longer than that, they often bolt not long after they're transplanted, or they stunt or stall, or they look fine but give you buttonheads. Broccoli is really a garden diva and wants everything 'just so'.

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Comments (7)

mulberryknob
13 years ago
Susan, I start my broccoli on a cool porch--temps get to the 50s at night after I start them, and they still tend to get a little leggy, but it's not a problem if they are growing well, because broccoli does root on the stems. For lack of space I plant seeds thickly and then after the peas go outside, pot them up and bury them deeper. Add the dirt and follow Dawn's advice to get them to the cool. I've been taking mine outside to get brighter light and some breeze and they are doing fine. And still on the cool porch at night.
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susanlynne48
Original Author
13 years ago
Sounds good. I will start taking them outside onto my porch during the day. Will an hour the first day be sufficient, increasing the time over the next few days until they can stay out all day?

What would I do without you guys? I had read about the fact that too warm temps can cause legginess, too, but I guess I thought that indoor temps of 70 degrees would not be much warmer than outdoor temps of 70 degrees. Of course outside you've got other cooling factors like the breezes (or in Oklahoma, the winds), where indoors we don't.

I have a ceiling fan in the kitchen where they are - I don't do much cooking other than microwave, though. The fan is about 4-5' away from the seedlings and they do sway in the breeze from it. I guess it's only pushing around the warm air, though.

The Packman seedlings seem to be stronger and sturdier than the other variety - forget the name.

What would you guys guess my target planting out date would be? End of the month?

Thanks again.

Susan
mulberryknob
13 years ago
Susan here in z6b I plan to have my broccoli in the ground during the first week in April. You might be able to go in a week earlier considering the heat island effect and a protected suburban yard.
Okiedawn OK Zone 7
13 years ago
Susan,

An hour the first day is fine, maybe even an hour and a half if you want to risk it, then gradually increase the dosage of outdoor exposure. I usually increase it an hour per day until they're hardened off.

Since we're talking about cool-weather-loving broccoli, it would be best if you get the plants out early to enjoy the cool morning temps and sunlight, although as they harden off they'll get more heat, of course.

I try to plant about a week before Dorothy does, although I'll hold the plants longer if we're having nights in the low 20s. Hopefully we're not going to have any more nights in the 20s, but you never know. This is Oklahoma so we could have a blizzard next week or next month.

I used to try to follow the OSU planting guide more precisely and plant broccoli earlier, but got buttonheads every time, so have found waiting until late March works out better in my location. I feel like I walk a fine line between planting broccoli "too early" and "too late". Like so many cool-season crops, its performance every year hinges on what the weather does.

I've grown maybe 15 different kinds of broccoli over the years and Packman has been the most consistent producer year in and year out, so I pretty much stick with it.

Dawn
susanlynne48
Original Author
13 years ago
I have some of the piracicaba seedlings coming along, too. I have read it is supposed to be like a happy medium between heading broccoli and broccoli raab, but sweeter than broccoli raab. I hope it is everything they say it is because altho we may be having a cold spell the end of this month, we are otherwise running what seems to me to be very warm temps early in the game this year and this broccoli is also supposed to be more heat tolerant as it was bred in Brazil.

I will start out with 1 to 1.5 hours for the seedlings. My front porch gets no direct sunlight, so I will acclimate first to temps and then to light. Indoors, I'm putting them in my spare bedroom where it is much cooler, so hopefully that will help, too. I finally got my other light setup going in there today.

Susan
zofia12
6 years ago
Hi