If you're noticing your houseplants pushing out new leaves right now, first of all — same. Hamilton has been getting some genuinely good light lately, and plants are absolutely clocking it. It's one of those moments where the instinct to do something kicks in, and a lot of people reach for fertilizer.
That instinct makes sense. I just want to make sure we're on the same page about what fertilizer actually is before you use it — because there's a really common misconception that I think causes more confusion than anything else in plant care.
Fertilizer isn't plant food. Your plant eats light.
Photosynthesis is how a plant feeds itself. Light hits the leaf, the plant converts it to energy, and that's the engine running the whole show. No amount of fertilizer changes that. If your plant is in a dim spot and not really moving, adding fertilizer isn't going to wake it up — it's just going to sit in the soil unused, and in some cases, that causes problems.
What fertilizer actually provides is closer to a multivitamin. It fills in trace minerals and micronutrients that support processes already happening. It helps. It supplements. But it does not drive growth on its own, and it cannot substitute for light. First, get the conditions right. Then we can talk about what to add.
Organic vs. Synthetic Fertilizer for Houseplants: What's the Difference?
Think of it this way: synthetic fertilizers are like espresso. Organic fertilizers are like coffee. Both contain caffeine — both deliver nutrients — but they process very differently through the system, and the experience isn't the same.
Synthetic fertilizers are concentrated and water-soluble, which means nutrients are immediately available at the root. They work fast, and that sounds like a win. But in a houseplant context — a relatively small pot, indoors, no rain to flush things through — that concentration can build up as salt in the soil over time. Too much salt interferes with your plant's ability to take up water at all. The thing you added to help starts working against you.
Organic options are slower. They work with the biology in your soil rather than bypassing it — feeding the microbial life in your mix, which in turn makes nutrients available to the plant gradually. That slower pace is actually really well suited to houseplants, which aren't in a hurry. They're not trying to produce a harvest or hit a deadline. They're just living, and they respond better to steady support than to sudden bursts.
This isn't a moral argument — both work. It's more that for most indoor plants, in most homes, gentle tends to be more forgiving.
Why contained soil changes the math
Outdoor plants have a lot of natural buffering. Rain dilutes. Soil volume is enormous. Root systems can range far. Your houseplants don't have any of that. Whatever you add stays in that pot until you deliberately flush it out, and root systems have nowhere to escape to if something's off.
That's why the lowest effective dose tends to be the right dose indoors. Not because more is dangerous, exactly — but because more is rarely necessary, and the consequences of over-supplementing in a closed system are harder to walk back than just waiting another two weeks.
What we keep on the shelf at Pinch
We carry Kelpy, which is a liquid kelp supplement made by a small female-owned business out of British Columbia. Twice a year, divers go into the water at the northern tip of Vancouver Island — where glacial mineral outflow makes the kelp grow up to three feet a day — and harvest it by hand. It's cold processed, which means the phytohormones and micronutrients are still intact when it gets to you, rather than being cooked off in production.
The NPK — that's the ratio of nitrogen, phosphorus, and potassium, the three main nutrients in any fertilizer — is 0.1 – 0.5 – 1.0. That's exceptionally gentle. One teaspoon in a litre of water, added right into your regular watering — that's it. A 250mL bottle makes 50 litres of solution, which is part of why we set up a refill station at the shop. There's no reason to buy a new bottle every time, and honestly a 250mL goes a long way for most people.
We carry it because it fits how we think about supplementing houseplants: support the conditions, work with the biology, don't push things harder than they need to go. It also backs that up with a 1% for the Planet commitment, which means a portion of every sale goes back to protecting the coastal ecosystems it comes from. That part doesn't hurt either.
When to actually use it — and what to watch for
Now that we're getting real light in Hamilton again, if your plants are actively growing, a gentle supplement every two weeks through the growing season is a reasonable place to start. If a plant is mostly just sitting there — especially something in lower light — hold off. You're not accelerating anything by adding nutrients to a plant that isn't really using them yet.
The rule I come back to is: fertilize in response to growth, not in response to the calendar. If the plant is moving, you can support it. If it's not, find out why before you add anything.
When the days start shortening again in fall, most houseplants slow down — and that's the cue to ease off or stop entirely until spring. Let the plant rest. It knows what season it is, even inside.
If you've been catching those Barton sunrises lately, you already know the light has shifted — and so do your plants. That window is doing more for them right now than anything you could add to the soil. Everything else is just support.
If you want to try Kelpy, we carry it at Pinch on Sherman Ave, refill station and all — bring your bottle back when you're running low. And if you're ever unsure what your plant is actually trying to tell you, that's exactly what Doctor's Appointments are for. Bring it in and we'll take a look together.fertilizer