When Should You Start Fertilizing Your Houseplants?
Water droplets on an asparagus fern.
The days are getting longer, and the weather is warming up a little, but it's definitely still winter in Alberta. So it might feel like it's a bit early for your houseplants to start putting out new growth, and to start fertilizing them. Honestly, though, your houseplants don’t really care what you think about when they should start putting out new growth.
When to Start Fertilizing Houseplants
Start keeping an eye out for new leaves beginning to unfurl or new buds. Once you start seeing new growth, you can safely start to fertilize your plants again.
The general recommendation is that most houseplants shouldn’t be fertilized in winter, only during their active growing season. Most guidelines say this is from April or May to October, but honestly, my houseplants usually start to perk up in mid to late February.
So, that’s when I begin fertilizing my houseplants. That said, I follow different guidelines for my African Violets.
When to Start Fertilizing African Violets
I usually start fertilizing my African violets at the end of December or early January. This year my African violets are not in great shape. They’re also not getting the kind of care they got last year. That’s because I’m annoyed with them because one of them keeps having mealybugs show up on it.
They haven’t been getting fertilized as much as they did last year, or as consistently. They also don’t have the same light they did last year because I’ve quarantined them in the only room with no other plants, the laundry room, with a small north-facing window.
They’re not very happy. Anyway, I usually start fertilizing African Violets in December, and I use African Violet fertilizer. I fertilize every week, so I use it at about half the recommended strength.
Houseplant Fertilizing Tips
My fertilizing routine for the rest of the houseplants is a little more haphazard. This early in the year, when they’re just starting to put out new growth, I begin to fertilize, but not frequently. Once a month for March and April is fine. I may move up to every two weeks in May.
The thing is, I’m not that organized about it. So I can’t actually tell you how often I fertilize. It might be more like every 8-weeks. Or every 6-weeks, or sometimes they might get two weeks in a row.
And this is where I say, “do as I say, and not as I do.”
There are two things that I think are the most important to remember about fertilizing your houseplants:
Mix your fertilizer a little weaker than recommended on the package.
Do your regular plant watering first, then, once the soil is damp, give your plants a small drink of fertilizer water.
The reason for diluting is that your plant can only use so much nutrients. So mixing it strong is basically wasting nutrients. Better to be a little lean on fertilizer than to over-fertilize, since that can cause other problems.
The reason for fertilizing after watering is that fertilizer is made of concentrated strong chemicals. Applying fertilizer to dry soil and relatively dry roots can potentially cause chemical burns on the roots of your plant, reducing their ability to absorb and use nutrients. Hydrated roots soak up the nutrients safely. So water first, then fertilize lightly after.
How Much Fertilizer Water Should I Give My Houseplants?
Honestly, I don’t give my plants much fertilizer water. I mix it in an old 500 ML pop bottle because then I know how much water I’m working with (since all of my watering cans are like 1.5 litres, or 2.75 litres… useless). After the plants have been watered, I’ll do another dump from the bottle, just enough to leave a small puddle on the surface around the plant that soaks away quite fast.
What Kind of Fertilizer to Use for Houseplants
I use the standard Schultz houseplant fertilizer for most things. I also have Schultz African Violet fertilizer which I also use on other plants that bloom, and I have Schultz Orchid fertilizer. I’ve never actually used it since my sister mostly looks after the orchids.