Question
Brown Tips
I have a few questions regarding one of my tropical house plants.
Firstly, I have a Rhoeo spathacea nana variegta (Variegated Hawaiian Dwarf) plant that has browning tips which I think may have to do with under-watering or fluoride sensitivity. I have it for about a year in a pot with actual soil (well draining), not potting soil. I water it with tap-water once a week(ish).
I have recently read that there are two theories regarding watering, one being watering more often and not soaking the soil, the other being watering less often but soaking the soil until water runs out the bottom a little. I have been watering based on the first theory. If the tips are due to under-watering, how should I water in the future.
With regards to the possible fluoride sensitivity, I have begun leaving the water in the watering can overnight to let the fluoride evaporate before I water the plant, is this enough?
I have included a picture of my artificial lighting setup in case that may have something to do with the browning tips. The window is a north-facing window and receives little to no direct light. The two clip on lights are actually meant for incubating chicks, but they are very reflective. This reflectivity means that some heat is directed towards the plants, but I did not think that would be a problem because the plants are tropical. None of the plants are showing signs of sunburn. The light (10 inch diameter) on the right has a 75watt spot gro plant light(blue) and is about 12-15 inches from the Hawaiian Dwarf. The left one (8.5 inch diameter) one has a 50watt spot gro plant bulb(also blue) is about 1.5-2 feet from the plants.
Any advice regarding my Hawaiian Dwarf would be much appreciated! Can I reverse the brown tips or at least prevent them on new leaves?
Thanks in advance!
(I am having trouble uploading more than one picture. I will attach the second picture as a follow-up question if I can't attach more than one here.)
AnswerHi Alanna,
The short answer is, no, it is not likely to be fluoride damage. You obviously are quite knowledgeable about plants so you deserve more than a short answer.
There is much confusion about fluoride and chlorine damage to plants. While both of those chemicals can cause foliage damage, it is very rare for them to be concentrated enough in water supplies to do damage. Swimming pool water has a much higher concentration of chlorine and can damage plants, but that does not apply in your situation. Although chlorine will dissipate into the air if the container is left open to the air for 12-24 hours, the same is not true for fluoride.
So if fluoride or chlorine are not causing the tip browning on your plant, what is? There are a several possibilities.
If your tap water is on the hard side, the mineral salts in the water will gradually build up in the soil and burn tender roots and cause leaf tipping. This is the most common cause of the problem and the easiest to solve. Use filtered or distilled water instead of hard tap water.
Allowing the soil to dry out too much between waterings will also cause mineral salts naturally occurring in the soil to concentrate and burn the roots. Likewise, incomplete watering - the technique you indicated you use when watering - also causes mineral salt concentrations or hot spots in the soil. Unless your plant is badly over-potted, then it is best to allow the top half-inch of soil to dry and then water thoroughly until some trickles through the drainage holes. This thorough watering helps flush excess mineral salts out of the soil.
I do not recommend using garden soil for indoor plants. It is much better to use soilless, peat-based potting mixes that have better texture and porosity. Garden soils are all different and have a wide range of minerals, nutrients and critters in them. In addition, the pH of garden soil is often not in the proper range for tropical plants. You might get lucky with garden soil, but the chances are very good that the soil will introduce any number of problems that can only be identified by having a lab soil test done.
I am not sure how to advise you on the soil your plant is potted in. Removing all of the soil to replace it with a better potting mix is very traumatic to the plant because it also removes or damages most of the fine root hairs that do most of the work. Perhaps it is best to flush lots of clear, mineral-free water through the soil. Then do a simple pH test and make sure it is in teh 6.0 to 6.8 range.
In your photo, the tipping does not look to serious, so don't overreact. Trim off the discolored tips, flush the soil and use non-hard water to water as I described. That will probably prevent any serious tipping in the future.
I cannot see the light set-up in the photo. However, your Rhoeo may do just as well with warm and cool white fluorescent bulbs, which are much cheaper to operate and do not generate heat. Of course, lots of direct indoor sunlight is best and will lead to thicker stems, shorter internodes and stronger color variegation.
Please let me know if any of this is unclear or if you have any additional questions.
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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC
Visit my website at www.HorticulturalHelp.com
I have written an article on that I will email for free to you (or anyone else) who sends a request to me at
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Please let me know if any of this is unclear or if you have any additional questions.
If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and nomination for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.
Need more information? Visit my website at www.HorticulturalHelp.com
or email me at
[email protected] or call me at 917-887-8601 (EST)
Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC
Visit my website at www.HorticulturalHelp.com
