Question
Plan to be gone for 1-2 months. Is there a devise to slow release water to my many individual houseplants. Having someone come in to water has not been successful in the past. Thanks

Answer
Hi Bets,

There are slow release materials that can be added to the soil. They hold and release water as needed. Soil Absorb and Terrasorb are two brand names. However, they can keep soil too moist for many plants and they may not last for 1-22 months, especially for smaller plants.

Wick irrigation is an effective, inexpensive method to provde water over an extended period of time. Fabric wicks are pushed through the pot drainage holes and several inches into the center of the rootball. The other end of the wick is left dangling outside the pot and put into a container that holds a reservoir of water. The larger the reserviir, the longer the plant will go. I use large plastic cake boxes that are about 14 inches in diameter and six inches deep as reservoirs. You will need a waterproof platform that sits in the reservoir but keeps the bottom of the pot above the water and allows the wick to dangle into the reservoir. A small plastic pot turned upside down works well. You can also use your bath tub as a water reservoir and put your plants on inverted pots in the tub.

Contact New Pro Corp. at 1-800-869-9285 for information on wicking material and ready-made wick systems that are reasonably priced and easy to install. Have them send a brochure so you can see how they do it.  http://www.newprocontainers.com/products/sub-irrigation.htm

Another alternative is a product called Sippers. These wicking devices act as stilts to raise plant pots above a reservoir of water while wicking the water to the roots as needed. They work well with plants in plastic pots smaller than 8 inches in diameter. Call 1-800-533-7661 for more information.  http://www.topsidersinc.com/sippers.htm

There are a dozen or more different types of self-watering planters. Some use wicks, some use inserts, some use vacuum sensors. All of them have some kind of reservoir that holds an extra supply of water that is not in direct contact with the soil, but is available, as the soil gets dry.

In general, self-watering or sub-irrigated systems work effectively on all indoor plants that need evenly moist soil. Although they can also work with succulents, I don't recommend it because it is easy to overwater them unless special precautions are taken.

The quality and consistency of soil is the most important factor in the successful operation of these systems. A light potting soil with good porous material (perlite, bark chips, peat moss,sand, etc.) is a must. Heavy soils (standard garden soil) will stay constantly wet and by definition they do not have sufficient air pockets to supply needed oxygen to the roots. Conversely, very sandy soils may not have sufficient wicking/absorbing ability to work successfully. Most system manufacturers will indicate the type of soil that works best with their system.

The wick systems are the easiest to install and cheapest to buy. The vacuum sensors are the most reliable and resistant to human error, but are quite expensive. The primary benefit of all these systems is that they allow you to go much longer between waterings, although not usually long as they advertise. But these systems will not solve any other plant problems such as light, pests, etc.

That is probably a lot more information than you need, but better too much than to little!

Please let me know if any of this is unclear or if you have any additional questions.

Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

You can E-mail me directly at: [email protected]

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