, Newburyport, MA

January 11, 2012

Tim's Tips: Caring for houseplants

Tim's Tips
Tim Lamprey

At this time of the year, many gardeners' thoughts turn to houseplants.

For those who have owned houseplants for many years, the winter gives gardeners time to catch up on transplanting and maintenance of the plants. Many people who want to get into gardening will try their hand at growing houseplants. Once the selection has been made, the age-old question comes up: "How many times a week do I water these plants?"

This is where the potential for trouble begins.

First, winter is the time when most houseplants need the least amount of water. They are in a semi-dormant time of the year. During this period, they may need more humidity to keep the foliage healthy, but the roots are not taking up much water. If the soil is always kept wet, the roots can actually die from too much water. As a matter of fact, the most common cause of death for houseplants is over-watering. So, the question remains, how often should you water your houseplants?

There are many factors that will influence how much water your houseplants will need.

As the days get longer and the plants begin to get more light, they will begin to grow again and need more water. The amount of water that is necessary will vary depending on type, but if you remember that now is a time when the plants need less water, and from roughly March to October, they will need more, you have a basis for how often to water.

The amount of humidity in the air will also determine how often you need to give your plants a drink. Dry air will pull moisture out of the leaves.

Humidity levels can vary from home to home. Temperature also causes plants to require more water. The warmer the temperatures, the more water that plants will need.

The amount of light the plant needs can also affect how much water it will require. Plants that grow in full sunlight will generally need more water than those plants that grow in lower light conditions.

Confusing as this may seem, there are some easy answers.

You can buy a tool called a moisture meter. It is probably one of the least-known tools that we sell. The moisture meter has a probe that is inserted into the soil. Within a few seconds, it will give you a reading of the soil's moisture level. Most of the meters come with a chart that will tell you what moisture level you should have for a particular plant. Once the moisture level falls below a particular point, it is time to water.

You should always water the soil with enough water so that it comes out of the bottom of the pot. The excess water should be dumped out. The reason for this is that salts can build up in the soil. Excess salt in the soil can cause browning along the leaves' edges and ultimately cause the plant's death. The salt naturally occurs in our water, and salts naturally occur in the fertilizer we use to feed our plants.

As you can see, there is no hard and fast answer as to how often you should water your plants. The conditions in your home and the needs of the plant are all determining factors. I guess the real answer is, you water the plants when they need the water.

Well, that's all for this week. I'll talk to you again next week.

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Tim Lamprey is the owner of Harbor Garden Center on Route 1 in Salisbury. His website is Do you have questions for Tim? Send them to, and he will answer them in upcoming columns.