The days are getting shorter here in Michigan and much cooler. Last week I wrote about moving your houseplants inside and this week I want to talk about fertilizing them and why you don’t need to in the late fall through early spring. Let me just say here that fertilizer is like giving your plant vitamins. It is NOT food for plants. The sun or electric light is the only thing feeding your plants. I’m not going to go in-depth about the nutrients and the specific types of fertilizers but touch on them briefly. We are discussing why our plants don’t need fertilizer in the winter. And if you decide you don’t want to fertilize your plants at all or at the very least once or twice a year, they would do just fine.

Types of fertilizer

There are many types of fertilizers to choose from including organic and synthetic. The most popular form is the type that “turns the water blue”. It is water-soluble fertilizer and the one many people use. I use Jack’s Classic 20-20-20 formula, an all-purpose fertilizer which indicates you can use it on most plants. There are liquid forms that are also added to water, which is the easiest way to get fertilizer to your plants, other than using a slow-release fertilizer or fertilizer stakes. Most of the plants you buy will have slow-release fertilizer already in the potting medium and are quite obvious as they are usually little balls that are a bluish-green or cream color. These slowly release fertilizer as the plants are watered and typically last from 3-6 months depending on the fertilizer. You won’t need to fertilize newly purchased plants for a few months as the slow-release fertilizer is doing the job.

Slow-release fertilizer sticks are an option. Not my favorite as I feel the fertilizer is too concentrated in one spot.

When should I fertilize?

Most often,  we are told to only fertilize our plants when they are “actively” growing. When is that happening? Aren’t plants always growing? Well, as long as they have light and water, they are most likely growing. The key is the rate at which they are growing. In the late winter/early spring, the days are getting longer and houseplants respond to having more light by sending out new growth. Then in the late fall, as the days get shorter, our plants slow down their growth. Less light means less food which means reduced growth. Depending on where you live, that time could be earlier or later in the year. If you live at the equator, the day and night length never changes so your plants are growing year-round. If you have a light garden, the light never changes for your plants so you can fertilize the same all year. If you live in the northern United States though, as I do, we have much shorter days in the winter than we do in the summer. So when the days begin to get shorter and our plants start slowing down their growth rate, it is time to either stop fertilizing our plants or at the very least, cut the amount used significantly.

SUPERthrive liquid fertilizer

How much fertilizer should I use?

This is an often asked question. How much should I use? If my plant is sick or struggling, I should double the rate to help it out, right? NO! Never fertilize a sick plant and never use MORE than the instructions call for. More is never better.  Fertilizer usually isn’t the problem with a sick plant. It may be not enough light or water or too much. Either way, figure out what is wrong with your plant and attempt to rectify the problem instead of throwing fertilizer at it and expecting that it will miraculously recover. I also never use the full strength dosage recommended on the package. I use 1/2 to 1/4 the strength called for. Our plants aren’t growing in optimum conditions in our homes (they would rather be in their natural habitat wherever that may be) and so don’t need the full strength recommended.

How often?

It is a common practice to fertilize your plants once a month. I recommend every fourth watering which may be more or less than a month’s time depending on the plant. Use the lower rate at that time OR you could use 1/4-1/8 the recommended dosage EVERY TIME you water your plants. That way, your plant is getting a steady dose of vitamins instead of all the vitamins at one time.

Winter care

In the short days of winter, let’s just focus on keeping our plants healthy, well-watered, and groomed during the dark days of winter and when they start showing signs of waking up in the spring, we can start them again on their vitamin regimen (fertilizer).

I hope your plants are doing well. How do you fertilize your plants? What kind of fertilizer do you use? Are you consistent or “hit and miss” like me? Tell me in the comments and have a great week.