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Tropical Milkweed under grow light issues.

Posted by eddie980 7b (My Page) on
Sat, Jan 11, 14 at 20:43

Hello fellow gardeners. This is my first year growing plants under grow lights. So I decided to grow some Asclepias Curassavica (commonly called Tropical Milkweed) for the Monarch butterflies (their host plant). The plants look great and are growing faster then expected. But most of the plants are starting to form little red spots or red edges around most of the leaves especially the bottom leaves. Eventually the leaves will turn a pretty yellowish red and fall off. What could this be? The plants seem fairly healthy except for this.
Here's some back ground information on them.
-They're under fluorescent grow lights ( the Jump start T5 brand)
-They're about 5 inches from the light
- They take about 16 hours of light a day.
-They're considered full to partial sun plants
-They like moist soil.
I think the problem might be the light. But would love suggestions. Thanks Ed.

Follow-Up Postings:

RE: Tropical Milkweed under grow light issues.

Here's another view of the plants leaves (notice edges). This picture was taken before I thinned out some plants.

RE: Tropical Milkweed under grow light issues.

Well, what I decided to do is remove the aluminum foil from the sides of the grow light. I heard aluminum foil helps give the plants more light. But maybe tropical milkweed plants don't care to much for a lot of light. Although they are full sunlight plants. Will see. If anyone knows what might be causing these red spots comments would be great. Thanks :^)

RE: Tropical Milkweed under grow light issues.

  • Posted by cghpnd 7 / N.Virginia (My Page) on
    Wed, Jan 22, 14 at 19:55

I was actually Just looking for an answer to this. I have the same issue.
I just noticed that my milkweed that was being wintersown had started sprouting. I brought them in and put them under lights. A few of the seedlings are about 3 inches tall. They've gotten the same thing your describing. I wonder what it is.
They are sitting on a black shelf. Lights are about 6 inches away from the lights.
How are yours doing?

RE: Tropical Milkweed under grow light issues.

I have observed this in a greenhouse and suspect it's normal, just part of the plant's growth. In other words, not pathological.

RE: Tropical Milkweed under grow light issues.

so jealous of your sprouts!! keep us posted :)

RE: Tropical Milkweed under grow light issues.

Congratulations on your new seedlings! They look very healthy to me, with great looking, stocky stems. The little seedlings might be old enough now to feed with a heavily diluted liquid fertilizer but that is your call. The only thing I can think of to suggest is to make sure you don't over water as the roots need to be able to breath. Based on your photos, it looks like you're doing a good job in this area.

The bottom leaves in your photos might be the seed leaves (cotyledons) and if so and I am remembering correctly, once the plant draws all the nourishment from them, they die and fall off. Maybe this is what is happening to these tiny lower leaves.

The coloring on the leaf edges is most likely normal. Depending on the variety of Tropical Milkweed you are growing, I've found some exhibit this type of coloring, especially the newer Red/Gold varieties.

Thank you so much for growing milkweed for the Monarchs.


RE: Tropical Milkweed under grow light issues.

  • Posted by cghpnd 7 / N.Virginia (My Page) on
    Fri, Feb 21, 14 at 13:22

Hey eddie980 How are your plants doing?
Only a few of the swamp milkweed I have under lights are still getting that Burgundy coloration on the leaves.. I have noticed that when I dont turn the fan on it gets worse..

Have you noticed any difference with things you are doing differently if any?

I have almost 300 swamp milkweed seedlings growing and 6 tropical..

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