Expert: Sarracenia Northwest - 3/3/2011

Question
Greetings,

I have been growing Drosera alicia for almost a year now. The problem is that some of the plants begin to show blackening and drying in the center growth point where all the new leaves begin drying along their outer edge before growing out. The center simply stops growing and dries out and blackens.

The D. alicia are kept in a 5 inch pot with 50/50 sphagnum peat/pelite bought from your company. They were repotted into fresh soil only a couple months ago and they have been showing signs of this problem before repotting.

They are watered with reverse osmosis water that reads less than 10 ppm when tested. They are kept constantly moist with about an inch of water under their pot at all times.

They are kept indoors 11 inches from 30,000 lumens of florescent 40 watt shop lights under which a variety of Cape sundews, Lance Leaf Sundews, and other carnivorous flora from a range of climates flourish. The D. alicia are kept along the outer edge so they will remain somewhat cooler.

Ambient environment is around 80 degrees by day and down to about 75 at night with humidity hovering around 50 percent at all times. All of the plants have been growing under the same humidity and have not been moved nor have they had any changes in air flow, just one ceiling fan moving the air around. No terrariums in use.

The plants capture their own gnats and fruit flies and are kept away from any and all fertilizers religiously. No chemcials or fungicides have been used on or near them their entire lives in my home and no pests are evident.

The soil and water cannot be the problem as when a plant shows with this drying, dead central leaf rosette I simply clip off the entire rosette to the roots and let the roots grow new plants, which flourish for a while until some develop the drying center again. I am caught thinking that they are either too hot, or are being burned by too much light, but the Drosera capensis would show similar problems as they also like the same environment. I have more Cape sundews than I can handle as it is.

Do you have any suggestions as to a change they might need in environment to keep this problem from recurring? I am thinking about moving them to a section of shelf with my Butterworts where they will only receive 6000 lumens about 6 inches from a set of florescents yet where they would be cooler.

This does not appear to be age either since a half gown plantlet has shown with this same problem recently while a flowering adult next to it is doing fine, no leaf problems at all.

Thanks for your help,
Christopher

Answer
Hi Christopher,

Thank-you for the detailed description.  I have to agree that your overall growing conditions sound very good.

It is probably your temperatures that are the problem.  The appearance you're describing are similar to what I see in ours sometimes during the summer.  D. aliciae definitely does best when it's cool.  Our best growth in this species in during the cooler times of the year.

Moving your plants to a cooler location is a good move.  The will tolerate slightly less light, so having them by your butterworts could work well.  In general, if you can get the nighttime temperatures down in the 60's that would be good.

Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com