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Yes! You can water the houseplants with leftover coffee

Q: Could you tell me how to get a stem to root? From what I understand, I need to cut off the end of a tendril of my dolphin plant and dip it into a root hormone. However, then what? Do I place the stem in a glass of water or place the dipped root into the same soil as the plant? I also read that bottom heat is good. What is bottom heat? Mine just finished flowering and I would like to root some slips for friends.

A: Once you have dipped the cut end into the rooting hormone, you want to stick it into a mixture of sphagnum peat moss and clean sand or either one. However, sphagnum peat moss is the preferred choice.

The peat should be soaked and wrung out as much as possible before sticking the cutting into it. This will provide the proper dampness and air mixture that is needed for rooting to take place. Bottom heat is obtained from a garden heating pad that maintains a constant temperature.

These can be purchased from local garden centers. It makes a very pronounced difference in rooting success. However, it causes the peat to dry more quickly, so you need to monitor the peat to be sure it stays moist. Mist with distilled water until the rooting is complete.

Q: We have a severe water shortage, so I want to look at the best use of the water that I have available. I'm wondering if I can water my plants with the leftover coffee. I make a full pot of coffee each morning, but we sometimes do not drink the whole pot, so throw the remaining coffee down the drain. By the time I get home at night, the coffee is cold, so this is when I would want to use it on my plants.

A: Coffee is "improved water" as far as a house or outdoor plant is concerned! I do it all the time with the houseplants in the office and at home.

We (actually my wife) take the leftover coffee grounds and mix it into the soil of our Square Foot vegetable garden. So far, we haven't seen any plants suffering from caffeine jitters! The coffee we drink in the office has a pH of 5.6, which is quite acidic.

When poured into the soil, the coffee will depress that pH temporarily without harming the plants. In fact, such a temporary drop tends to make trace elements, such as iron and copper, more readily available. For those who want to attempt growing blueberries in a high-pH soil, try mixing the used coffee grounds in to depress the pH more permanently to achieve the level needed for good blueberry production.

Q: I purchased three crotons (banana, petra and mammy), but I didn't realize how difficult they would be. My petra and banana are doing fine, but the leaves on the mammy are getting soft and wilting. What is the problem?

A: I can't say for certain with the information provided. It could be due to overwatering, poor draining soil, nondraining container, bacterial disease or root rot. Generally, these are some of the most problem-free houseplants on the planet. Crotons even stand up to benign and willful neglect. The overall wilting that you describe does not bode well for the plant, so I would suggest dumping it.

Q: I think what I have is a crown of thorns plant that is several years old. All of a sudden, it is droopy, losing leaves and turning yellow. How can I revive this plant?

A: A crown of thorns plant is almost indestructible. The only things I know of that take this plant down is too much water or the temperature is too low. If the plant is or has not experienced either or both of these problems, then I don't know what is wrong. Sorry!

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