Potassium Fertilizer

Once a week in spring and summer at 1 to 2 teaspoons per gallon, in a watering can or through a hose-end sprayer on the 2-teaspoon setting, and every 4–8 weeks in fall and winter. Potassium Fertilizer is straight potassium with no nitrogen or phosphorus, so use it as a supplement alongside your regular complete feed, on the same schedule, and only while a potassium boost is what your plant needs: through flowering and fruiting, or while correcting a deficiency.

Scorching or yellowing along the edges and tips of older, lower leaves while the leaf centers stay green. Potassium deficiency shows on older growth first because your plant moves its potassium to new growth. Weak, floppy stems, poor or low-quality fruit and plants that struggle in heat, drought or cold are the others, and Potassium Fertilizer targets exactly those. If instead you see whole leaves yellowing evenly, that points to nitrogen; yellowing between the veins points to magnesium or iron, not potassium.

Potassium regulates water movement in and out of cells, which drives everything from stem strength to drought and cold tolerance. It’s central to fruit quality, moving sugars into fruit and supporting size, sweetness and color, which is why it matters so much for tomatoes, peppers and fruit. Unlike nitrogen, it doesn’t push leafy growth; it strengthens and matures your plant. Potassium Fertilizer delivers it on its own, as 10% soluble potash with kelp and 1% sulfur, for the flowering and fruiting stretch when your plant draws on it most.

No. Potassium Fertilizer is 0-0-10, with no nitrogen or phosphorus, and every plant needs nitrogen to grow and phosphorus for roots and flowering. It’s designed to work alongside your regular complete feed, including any other TPS fertilizer, as a targeted top-up: to correct a potassium deficiency, or to support fruiting and stress tolerance during the season. Use both together, on the same schedule, and let the balanced fertilizer cover everything else.

Gradually, and mostly on new growth. Scorched edges on existing leaves won’t reverse, but leaves that emerge after feeding come in without them, stems firm up as your plant takes up potassium, and fruit that develops after you start shows better quality over the following weeks. Potassium Fertilizer supports processes that unfold across a season, so the clearest results show over a full fruiting cycle of consistent feeding rather than in a few days.