Lavender leaves dying at the tips

Hello--

I have a lavandula vera plant that I started from seed about May of last year. The plant was started indoors in an 8 oz. plastic cup. When it grew large enough to tolerate the hotter temps, I transplanted it into a 2-quart pot using a mix of 2 parts Miracle-Gro Organic Choice potting soil and 1 part perlite, and slowly acclimated it to the outdoors. Around the beginning of November, it was brought indoors, and (since my pepper plants are taking all of my window space) I put it under a 26-watt cool white "daylight" compact fluorescent bulb. The first two months the plant seemed to thrive, quickly growing new, bushy shoots. Over the last week or so, I've begun to notice that the tips on some of the slightly older leaves are starting to brown and die. I know this can be a symptom of overwatering, but I let the soil dry out pretty well between waterings, but not completely (I use a moisture meter with a scale of 1 to 10, and water the plant when the meter is reading around 3 about 2" from the surface.) I have included a picture of some of the affected leaves. Any and all help is appreciated!

--Jordan

P.S.--

The plant is given a fish emulsion watering every five weeks, is being kept 3 1/2" from the CFL bulb (did the feel test with my hand at the top of the plant; not hot at all), and the lamp is kept on 24/7.

I don't know if this is contributing to the problem, but most plants are better off if you turn off the lights and let them have a night-time rest. I don't know of any plants where it's beneficial to leave the lights on 24/7, and it could be bad for some. For seedlings I'll usually leave lights on 16 hrs, but for grown-up plants like yours if I have them inside under lights I'll try to stay fairly close to how many hours of light they'd be getting outdoors at that time of year.

Buildup of salts in the soil can also cause browning leaf tips--since you're being careful on the watering you're probably not really flushing out the soil well so those salts can build up over time.

Thanks ecrane, they're going on my schedule now!

I agree with the 18/6 light schedule, and the possibility/probability of either over-watering or a high level of soluble salts in the soil ..... all the usual suspects. Mites are also a real possibility on this plant. It would be easy to thoroughly flush the soil several (5+) times the next time it needs watering, and I would do that. I would also get the plant on a fertilizer program that uses a fertilizer RATIO of 3:1:2. There are a number on the market, my favorite being Foliage-Pro 9-3-6. HOW you implement the fertilizer program depends on your watering habits and soil, but even with the added perlite, the MG soil is going to be more water-retentive than the plant prefers.

There's a lot that can be discussed, but I'll let you decide how deeply you want to delve. ;o)

Al

A little update: The plant was repotted and put on a constant 16/8 on/off light schedule, and the plant has dropped all of its "wounded" leaves, and doubled in size since the original post. Thanks for all the help and suggestions!

--Jordan