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rangerbubba

Broccoli leaves turning purple

rangerbubba
15 years ago

I have a few small Broccoli di cicco transplants that I raised from seed that I planted in my raised bed about 2 weeks ago. Yesterday I noticed that a few of the lower leaves were turning purple. The newer growth looks fine, although the plants are not growing very quickly. My raised beds are filled with a pre-made mix that had lots of organic matter and expanded shale. Drainage does not appear to be an issue. I haven't tested the ph of the bed.

I've heard with tomatoes that purple on the leaves can be a phosphorous deficiency. Could this be the same thing?

Comments (21)

  • denninmi
    15 years ago

    Yes, that's exactly what it is, a nutritional deficiency. Hard to say exactly what nutrients, since the deficiency symptoms of most are pretty similar.

    Throw some good, all-purpose fertilizer, preferably one that also has micronutrients, on them, and they should be fine.

    Some of the purple tinge might just be acclimation to the outside weather as well. But, can't hurt to fertilize (well, as long as you don't overdose them).

  • stephen_albert
    15 years ago

    Many plants leaves and stems will deepen in color when temperatures drop. If you did not harden off your transplants before setting them out or if your outside temps have dropped to near freezing it may be a natural reaction.

    Here is a link that might be useful: http://HarvestToTable.com

  • rangerbubba
    Original Author
    15 years ago

    They were hardened off for 2 weeks before I planted them, sometimes in cooler temps than what we're having now. My instinct last night was to treat them with some 5-3-3 fish/ seaweed/ molasses emulsion diluted 5T per gallon. Hopefully that will help. I've heard broccoli is a nutrient hog and there still a lot of rough matter in the mix they're planted in. I guess I'll just complete my decent into gardening madness and spring for the electronic soil tester! :) Thanks, all!

  • staticx
    15 years ago

    also becareful you dident get an ornamental type of it.

  • bella_trix
    15 years ago

    Could you post a picture of them? I've raised De Cicco for the past two years and I vaguely remember that they took on a purplish cast in the garden. I think it may just be the variety. Unfortuately, I don't have access to my photos right now; I'll take a look tonight.

    If you can put up a photo, it might be easier to tell if it is a nutritional problem or just natural coloring

    Bellatrix

  • rangerbubba
    Original Author
    15 years ago

    Here are the pictures:
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    These are 3 different plants. I put the white paper behind them so they would show up a little better against the mulch.

    I got an electronic soil tester. & tested the bed today. the ph throughout the bed is 7, so that's good. The fertility rated at the high end of "too little." (Its a needle gauge). I gave the broccoli & other plants in the bed another douse of the 5-3-3 fish & seaweed mix, which is the most balanced stuff I have right now. I guess my next step is to get the test tube kit so I can see exactly where I'm lacking on the NPK. What makes me nervous is that I'm getting ready to plant my tomatoes in the same bed in a week or two.
    I suspect the rough stuff in the bed might be eating up a lot of nitrogen. Would it be best to mix a few bags of really finished compost in where I'm going to plant, or to apply a fertilizer to what I've already got? I'm trying to do all this organically.
    Thanks to everyone for their prompt responses!!! I've been lurking on the forums for a while, and have been able to answer most of my questions with a search. Hopefully this will help others with the same problem.

    Here is a link that might be useful: Broccoli plants

  • engineeredgarden
    15 years ago

    Boron.....a deficiency of boron makes the leaves of leafy vegetables turn purple.

    EG

  • bella_trix
    15 years ago

    I took another look at my De Cicco seedlings and they were not the ones that turned purple (it was the Mammoth cabbage). Your pictures do not look good (well, the plants in the pictures), although the new leaves look OK, so that's encouraging.

    I'd be suspicious about the wood mulch. I've heard it is not recommended in the garden (except paths), particularly not right against the plants. At the least, I'd pull the wood mulch back 6-12 inches from the plant or consider getting rid of it entirely and replacing with compost. Do you know anything about the source of the wood chips? I'd hate to think that you have black walnut wood chips mixed it. It definitely inhibits plant growth, but I don't know if they turn purple first.

    Hope you find the solution,
    Bellatrix

  • rangerbubba
    Original Author
    15 years ago

    The mulch is cedar. I'll go ahead and pulln it away from the plants some.

    How exactly would one add boron to their soil?

  • macheske
    15 years ago

    They just look cold to me. The broccolini I planted outside last year looked like that for a few weeks and then went green when the ground warmed up a little.

  • thefarmguy
    15 years ago

    well after looking at the frozen soil here today,,,your plants look pretty good...look to me also like they are just cold, i grew geat broc through cardboard with soft wood shavings covering, right up to the stems, it is a good thought that this mulch might keep the soil from warming as quick as bare ground. broc on

  • knittlin
    15 years ago

    "How exactly would one add boron to their soil?" Liquid seaweed. It has a lot of micronutrients including boron. If your plants are still purple after you warm them up, you might want to try some seaweed. It's not only good for boron but for stressed plants in general. It's like a natural SuperThrive.

  • Joe Bergeson
    5 years ago

    I own a greenhouse and my young plants (of many different types of plant) often have purple lower leaves. The new growth appears fine, but the lowest leaves that turn purple don't seem to recover. I found this thread trying to research what is going on. It's odd that I can't just run a google images search and see it right away.

  • LoneJack Zn 6a, KC
    5 years ago

    Might be because it's 10 years old!

  • yolos - 8a Ga. Brooks
    5 years ago

    My soil test said to "add 1 tablespoon of borax per 100 feet of row to broccoli and root crops such as turnips and beets. This can be applied by mixing borax thoroughly with approximately 1 quart of soil in a container and then applying the mixture along the row. or it can be mixed with a quart of water and applied to the soil in solution". I THINK this is to supply boron but the test did not actually say it lacked boron??????????

  • LoneJack Zn 6a, KC
    5 years ago
    last modified: 5 years ago

    yolos - Greensand also has trace amounts of boron in it. Greensand is one of the components of most granular organic fertilizers like Gardentone. I've read that some varieties of broccoli require higher amounts of boron than others. I believe Arcadia is one of them IIRC. I've never had good luck with it even when I added a teaspoon of Borax to a couple gallons of water and watered with it. The heads just don't want to form and stay tight. Anybody want some Arcadia seeds? I've given up on it in my garden.

    I've got a box of Borax and at the rate I've used it so far it will last me 10 lifetimes!

  • Amy W.
    5 years ago

    Yes - in a soil report, the borax is to add boron. In most of the Eastern states and in the Pacific Northwest, soils generally are low in boron. There is a map on the 20 Mule Team Borax site that shows where the low-boron soils are. It's a big area!


    I am in Georgia, and soil reports from UGA have the recommendation that YOLOS cites, to use one tablespoon of borax for 100 feet of row. Boron is an essential micronutrient, and it is totally possible to use too much. Kelp meal or liquid seaweed (like knittlin suggests) may be safer options than borax, because they are less concentrated. Follow package directions, and the bonus is that lots of different micronutrients will be included, not just boron.


    Purple leaves on other plants, like tomatoes and corn, often indicate phosphorus deficiency. There can be plenty of phosphorus in the soil, but in cooler weather those two crops can't take up phosphorus as well as they do in warmer soils. Broccoli is a cool-season crop, though, so I would have thought that it could get its nutrients in cooler soil. It's an interesting puzzle!


    -Amy, who used to work at Cooperative Extension in Cobb County, in horticulture

    (Earlier this monthI wrote about boron on my garden blog - how lucky is that?)

  • LoneJack Zn 6a, KC
    5 years ago

    Amy - welcome to gardenweb! Nice blog! It's always good to have another knowledgeable member posting.

  • yolos - 8a Ga. Brooks
    5 years ago

    Thanks for that info Amy. I went to your blog and found exactly what I needed. My soil tested low in Potassium so your post about how to get potassium in soil was timely for me.

  • Amy W.
    5 years ago

    Hi yolos, I am glad you were able to find something useful in my blog! I love growing food plants, and as an organic gardener in the Southeastern US, I have run into just about every kind of problem there is. Eventually, most of that will make it onto my blog, so other gardeners won't have to make all of my mistakes!


    And thank you, LoneJack, for the kind comment. It is good to be able to support other gardeners with all that I have learned over the years! Gardeners are such great people.