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Ron Smith answers questions about flowers, trees, gardens and shrubs.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: Are there any special considerations when growing herbs indoors? (Lakota, N.D.)

A: Herbs that are adaptable for growing as indoor plants are thyme, chives, parsley, marjoram, oregano, rosemary and the shorter forms of basil. What you need for success is plenty of light from window sills or fluorescent units. I would suggest utilizing both sources. Place the light unit on 14-hour days using an automatic timer. Normal room temperature is OK, but lower the temperature by 10 degrees at night if possible. Place the herbs together and try to have a gentle fan blowing across the foliage most of the time. The herbs will do better if grouped and set on a tray of pebbles that are kept wet. Use only pasteurized potting soil and allow it to dry slightly between waterings. Be sure the containers are free draining.

Q: I typically start my own bedding plants each spring using a small greenhouse that I purchased. The problem is that my seedlings develop a very poor stem and root system. They also become leggy before they fill out. What am I doing wrong? (Jamestown, N.D.)

A: Spindly, weak growth is the result of keeping the air temperature too high and not having enough light. Supplemental lighting is needed to start most seedlings, even in greenhouses.

Q: Do you have any recommendations for a beautiful, low-maintenance flower or plant that would make a nice addition to a small apartment? The apartment receives a moderate amount of light, but has very little window space. I inherited a beautiful flower vase that I would like to use. Any thoughts? (e-mail reference)

A: If it is a flower vase with no drainage holes, you will have a problem. The soil eventually will sour from anaerobic conditions and end up killing the plant. If you can use the vase as a pot holder with a plant in it, then there are plenty of plants to consider. Because of the low light situation you are in, flowering plants would be a poor long-term investment. With foliage plants, you would have a better chance of success if you added some fluorescent light or a plant light that you could set on a timer to run for 12 hours per day. Some tough houseplants that will thrive even with benign neglect include corn plants (dracena), Chinese evergreens (aglaonema), piggyback plants (tolmiea), dumbcanes (dieffenbachia) and snake plants, which commonly are known as mother-in-law’s tongue (sansevieria). Spider plants (chlorophytum) will do well, but are best used as hanging basket plants in a window. All of these will survive and do quite well in subdued light as long as they are not overwatered. Overwatering is the biggest killer of houseplants.

Q: Can you advise me on how often to water a China doll plant I purchased? My plant has been dropping leaves at night. My daughter thinks I’m not watering the plant enough. I have the plant sitting where it receives afternoon sun for a couple of hours a day. I use propane heat to warm up the house in the morning. We have spider mites in our house, so I put granules on the plant. Was that the wrong thing to do? (e-mail reference)

A: China doll plants are fussy. It didn't like being taken from the florist shop and absolutely doesn't tolerate cigarette smoke or inconsistent watering. Allow the soil to dry between watering. Overwatering will result in the leaves turning black and dropping off. Underwatering will cause the leaves to turn crisp and drop off. This plant also is susceptible to mealy bugs and spider mites. The best way to control these pests is to mist the plant regularly with tepid water. Make sure the plant gets as much winter sunshine as possible.

Q: I would like the names of different types of plants that can grow or survive with the roots emerged in water. I want to take a large, clear vase and decorate it with rocks and sea shells at the bottom. I also want to put some tropical fish in it and have the plant growing out of the vase. (e-mail reference)

A: Many plants will do fine in a water medium. The water needs to be changed or aerated on a regular basis to keep toxins from building up. Nutrients will need to be added on a spoon-feeding basis to keep the system going for any significant period. I've seen bamboo, African violets, spider plants, lilies, avocados and more thriving with their roots in water if maintained properly. Other than cacti and succulents, the choice is yours!

Q: I have an 25- to 30-year-old snake plant that I inherited from my mother. I am not sure what species it is, but it does not have a yellow rim around its leaves. I have a question about the yellowing that has occurred in the last few days at the core of the stalk. The inner 5 inches of the stalks are yellowing, but the rest of the stalks are green and healthy looking. I am wondering about root damage or other problems. I have to admit that I’m not good at watering it regularly. It sometimes has gone weeks to a month without being watered. I never have had problems with this plant before. I am wondering if the pot is too small or if there is a problem with the soil or drainage. I definitely do not want this plant to die. It has been around as long as I have. (e-mail reference)

A: You probably have some root rot taking place in a plant that old. Remove it from the pot and divide the crown. Get rid of anything that looks like it might even have a little rot. Take a couple of cuttings as well. The cuttings should be about 8 or 9 inches long. Stick the cuttings in a sand/peat mix and keep moist. In two months, a new plant will appear from the base and the cutting leaf itself eventually will deteriorate, which you then can dispose of. This gives you a little backup insurance in case something happens to the mother plant. Like any houseplant, don’t overwater it. Keep the plant it in a container that has good drainage and dump out the excess after watering.

Q: Two of my favorite houseplants have started growing a pale yellow mold in the soil next to the plant. The first time it happened (8-year-old dracaena), I figured that it was some kind of freak thing, so I did my best to scrape it all away and added new soil. Now my Christmas cactus is doing the same thing. Is this fungus or whatever dangerous to the plant? How can I get rid of it? How do I avoid getting it again? I have been reading up on houseplants the past year and find the advice of the experts conflicting. One expert says I should water a plant until water runs out the bottom and then hold off on watering again for one to four weeks, depending on the time of year. Another expert says I should water the plant up to three times a week, but use smaller doses. How can both of these methods work? I like the idea of doing less watering, but it's nearly impossible to water larger houseplants until they drain out the bottom. It was after I tried doing this to my dracenea that I grew the mold. (Anchorage, Alaska)

A: Experts will tell you what they experience under their conditions, which often are not well explained. Generally, you should know the approximate volume of the container the plant is growing and then put approximately that amount of water in each time. This will result in the water coming out of the bottom of the container because it is filled with soil. I find this is fine for a small container, but a headache for a larger one, so I don't do it. Instead, I choose to water a couple of times a week (when I think of it) using the same amount of water each time (1/2 gallon). Believe it or not, the plant does beautifully for me under this treatment. So what is my expert advice? Go back to what you were doing before all the experts confused the issue. The fungus you're seeing is a saprophyte, not a parasite. It will not harm your plant. Simply scrape it off or repot.

Q: Do you think that clay pots are better than plastic for indoor plants? I just love the look of the terra cotta pots so much better, but I am wondering if I am doing any good for my plants. (e-mail reference)

A: It is tempting to say that clay pots are better than plastic. However, I never have seen a plant grow with any difficulty in either one as long as there was free drainage. Many people feel the way you do about the look of terra cotta pots. Some people like plastic pots because of their ease in cleaning, lighter weight and greater color range for interior decorating. The choice is up to the individual.

Q: The tips of the leaves on one of my houseplants always turn brown, but I am not sure why. (Stanley, N.D.)

A: A number of factors could be causing the brown tips. Fluoride in the water or potting soil can contain amendments, such as perlite or vermiculite. It also could be the result of a salt buildup, cold draft or too much sunlight at once. My best guess is that it is a fluoride burn or minor soil toxicity.

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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