- Author: Carmen Kappos
“Overwatering is the number one killer of houseplants,” says Mr. Ernesto Sandoval, Manager and Curator of the UC Davis Botanical Conservatory. Overwatering encourages disease, pests, and can smother roots that need oxygen. With overwatering, roots can die and rot.
When to water depends on many things: the type of plant, the amount of light, temperature, the potting mix. All these things have an effect on when the plant will need water. So how to tell when to water?
Here are some good tips on determining when to water your houseplants.
- Your finger is a really good moisture meter. Use your finger to check for moisture in the top 1” of potting mix.
- Leafy plants: let the potting mix start to dry until barely moist between watering.
- Succulents and stem succulents: the top 1” of potting mix should feel mostly dry between watering.
- Get familiar with how heavy the pot is right after watering, dry potting mix is much lighter in weight than when it is wet.
- Dry potting mix is also lighter in color than wet potting mix.
- Water so that some water drains out the hole in the bottom. This ensures that the water has gone into the entire pot and has reached the root zone.
- Do not let the pot sit in water, empty the saucer or tray after watering. Drained water contains salts and minerals that can be reabsorbed into the pot. This briny water is not good for the roots.
- Pots can be elevated with material like pebbles, in the tray, to keep the pot from touching drained water.
- Usually tap water is ok to use for most houseplants, however softened water contains salt that will quickly kill plants. Water with Boron should not be used on container plants.
- Water from wells may be ok to use, it depends on the amount of minerals dissolved in the well water.
- If there is a buildup of crusty minerals on the pot or potting mix, gently remove the crust and flush out the pot with clean water that does not have minerals, then let drain.
- Use a well-draining potting mix. Most commercial potting mixes hold too much water. Small pumice rock sold at plant nurseries can be added at half the total volume to improve drainage in potting mixes.
The UC Davis Conservatory houses over 3000 plants in more than 150 different plant families. Responsible for the care and development of the collection, with a degree in plant biology, Mr. Sandoval has watered and cares for many plants. In his video talk on houseplants Mr. Sandoval advises to err on the side of under watering. Check out his talk on houseplants at: https://youtu.be/n60Iia0XxUE
Bonus tips from the editor: If you're seeing lots of little gnats buzzing around the pot, you're probably keeping the plants too wet. Seeing lots of burned edges on leaves? Either you have accumulated salts or may be getting plants too dry between waterings.
What more appropriate house plant than a String of Hearts to help celebrate Valentine's Day? A generous friend of mine who is a lifelong gardener and also a master gardener in our Inyo-Mono Master Gardener group gave me her plant when I expressed interest in the lovely long trailing stems and heart shaped leaves. They are a succulent leaf about an inch wide, with a wonderful grey pattern providing quite a lot of visual interest. The backs of the leaves have a purple hue. Along the stems, the plant also produces funny little flowers which are about a half an inch long and vase-shaped with purple stamens protruding out of the end of the flower. These small flowers start out white, turning purplish as they age.
The botanical name of String of Hearts is Ceropegia woodii, also classified as Ceropegia linearis subspecies woodii. Like many of our fascinating house and landscape plants it originates in Africa where it is found from Zimbabwe to South Africa. The plant was officially collected in 1881 by John Medly Wood. J.M. Wood had many plants named after him, he was a self-trained botanist and, for a span of about 31 years, was the curator of Durban Botanic Gardens which is still an active botanic garden located just outside of Durban, South Africa. J.M. Wood collected the plant which was hanging from rocks, and as house plants they are wonderful in hanging baskets or looped up and over a frame or trained around a circular frame.
Ceropegia are classified in the Apocynaceae Family, Subfamily Asclepidia, the Milkweeds. All of the Ceropegia , scientific name from keros meaning wax and pege meaning fountain, have similar vase shaped flowers leading to common names like Dutchman's Pipe and Wineglass Flower. In their native habitat, the flowers are commonly pollinated by small flies. Tiny hairs on the inside of the flower trap the flies for a short time, the flies pollinating as they work to get out and emerging with pollen on their bodies. As they are fly pollinated, some of the flowers have an aroma only a fly would love, but on String of Hearts I have not detected any bad odor. Other common names for C. woodii are Sweetheart Vine, Hearts Entangled & Tangle Vine due to its ability to tangle each stem very readily. That is a characteristic I can vouch for. I wanted to see how long each stem was on my gift plant, and had quite a wrangle straightening one stem out to measure. Some websites list the stems as growing to 4 feet, but the stem I measured came to just short of 14 feet.
Ceropegia woodii needs a fast draining potting mix or the tubers and roots may rot. A commercial cactus mix works well, adding more perlite or sand to the mix to help with drainage. Water moderately and let the pot dry out between watering. Be careful not to overwater especially in the winter months. They only thrive outdoors in Subtropical and Tropical areas. In the Owens Valley where temperatures are high in the summer a potted String of Hearts may be taken outside to partial shade, but be careful of night time lows as they do not do well in temperatures lower than 60 degrees. In the house provide bright light for 3 to 4 hours per day in full to partial sun, doing well in normal room temperatures in the 60 degree range up to 75 degrees Fahrenheit. They seem to perform well in a crowded pot, so should not need repotting often. When it is time to repot, it is best done in spring, before they really start growing again. During the growing season, fertilize sparingly with a low nitrogen houseplant fertilizer at half strength of usual dosage, this could be done as much as once a month. Common pests are mealybugs, aphids and scale insects. Also watch for these at the soil line where they may go undetected.
Ceropegia woodii has the reputation of being easy to care for, very accepting of neglect and has a wonderful appeal with its cascade of heart shaped leaves. With common names like Hearts Entangled, Sweetheart Vine and String of Hearts who could resist treating your valentine to such a special plant?
Royal Horticultural Society rhs.org.uk
SANBI South African National Biodiversity Institute www.sanbi.org
Plants Rescue www.plantsrescue.com/ceropegia-woodii/
- Author: Lynn Galloway
Autumn is definitely my favorite time of the year. The vibrant colors, brisk temperatures, and harvesting the last of my vegetable garden are among my favorite personal indulgences. But I wonder, how to survive the long winter without my garden to tend and my fresh flowers to arrange. My answer: refocus my attention to my indoor plants which tend to become a little neglected during the summer.
My love of houseplants began years ago in the early seventies, when indoor plants were all the rage. My friends and I would share clippings and collectively beam at our successes and our green thumbs. Over the years, I have remained faithful to the indoor plant, even though for a short time silk plants seemed an easy solution in keeping green with no care.
In 1974 I was gifted an umbrella plant, which arrived in a gallon pot containing three small trees. Only one has survived. Through the years we have battled white flies, scale, gnats, and ants. I have repotted, pruned, leached, soaped its leaves, and fed my Schefflera. Every autumn, I take my tree outside and give it a good soaking and shower. I check to see if it’s time for repotting.
My tree now stands about four feet tall. It is very compact and full, as I prune it every few years. I think one of the main reasons for my success with my umbrella plant is that I only water it once a week, and it’s in a great location. It receives filtered sunlight most of the day, but no direct sun. I also don’t overfeed my tree. When it begins to lose some color, I add a little fertilizer, the kind you mix with water. I follow the directions to the “T” and don’t overdo it. My umbrella plant is approaching its fortieth birthday! This year, I am going to attempt to start a couple of trees from clippings.
I’ve had good luck with many houseplants over the years. Another one of my finds is my Ficus benjamina tree. I purchased it at a yard sale. It looked very pitiful, and the small amount I paid for it more than covered the cost of the large pot it was housed in. When I took it home, I rinsed it off, took it out of its pot (which was way too large for it), and repotted it in a smaller pot in new potting soil. My tree now stands over nine feet tall, and I’m proud to say that it looks fabulous! I water it once a week, and follow much the same care as my umbrella plant. Sometimes if my plant becomes stressed, it loses many of its leaves. If you find a good spot for your weeping fig, keep it there. They really don’t like being moved!
Happy indoor gardening!
- Author: Dustin Blakey
When a Christmas shopping urge suddenly hits, you may end up adopting a poinsettia. Fortunately they are a lot easier to take care of than a puppy. Actually it's worth mentioning that they are NOT puppies. You are not obligated to care for them for years. Your main goal is to keep it alive through Christmas. After that, the dumpster makes a good home.
To keep a poinsettia alive through December 26 requires only two things: don't let it freeze and keep it well-watered.
The most common problem with poinsettias at home is letting them get too dry. When that happens, the leaves burn and fall off. This leaves you with a few naked stems adorned with a some sad, little bracts. Something like a potted plant version of Charlie Brown's Christmas Tree. It will not grow new leaves to fill in the bald area by Christmas Eve.
It's very important to check your plants every day for water. The best way I've found to do this is to pick them up. If they are lightweight, they need water. Fingers don't tend to work well as a gauge in this case. Note that I'm not saying to water them every day, just to check them. Nearly as bad as being too dry is allowing them to sit in a continual pool of water. When the root zone is constantly saturated, they tend to get diseases. This will conveniently kill them off right before all your fussy family comes to visit.
I usually follow this routine:
- Pick up the pot. If it's light, I water it thoroughly.
- I come back in about 20 or 30 minutes and check it. If there is still water standing in the sleeve and the soil is wet, I drain out the excess from the sleeve. You don't need to fertilize them.
- Repeat daily.
After the holidays, I throw the plant out. Poinsettias make fine, green house plants but realistically, you won't get it to turn color for next year's holiday season, and it will be tall and leggy. Commercial growers use plant growth regulators and careful adjustment of temperature to control the height. They (and you) can initiate flowering by regulating day length, but it is hard to find a dark spot in the house. Plus it's a real pain to move the plant in and out your closet every single day at 4:30. Just toss the plant out and buy a new one each year. A nurseryman will be grateful for the business, and that will cancel out any bad karma from throwing out the plant.
If the thought of tossing out a perfectly good plant still disturbs you, send it home with a visiting guest. You'll remain guilt-free and maybe smooth out some family discord in the process.