Fertilizer Dilution Calculator
Enter the label's dose, your watering can size and the season. The calculator gives the millilitres of feed per can, the per-plant figure, and the calendar that decides when feeding stops entirely.
Labels print greenhouse doses for greenhouses. This one halves them for windowsill winters, explains why overfeeding looks like underwatering at first glance, and gives the flush that fixes the salt crust when enthusiasm won.
How to use
- Read the ml-per-litre dose from the bottle - not the scoop table for outdoor beds.
- Set the season: half strength from autumn to spring, full only in active growth.
- Water first if the soil is dry - feed goes into damp soil, never into parched roots.
Frequently asked questions
How much fertilizer should I use for houseplants?
The label dose, halved for indoor winter conditions, every two to four waterings in the growing season. Greenhouse labels assume professional light and airflow; a windowsill metabolises a fraction of that.
What happens if I over-fertilize plants?
Salt burn: brown leaf tips and margins that mimic underwatering, white mineral crust on the soil, sometimes a fertiliser smell. The fix is a thorough flush with plain water and a month off feeding - then a weaker dose.
Should I fertilize plants in winter?
Almost never - resting plants cannot spend nutrients, so the feed becomes the salt crust that burns roots in spring. Resume weakly when new growth starts, and let the calendar, not the bottle, set the rhythm.
Can I add fertilizer to dry soil?
No - fertiliser onto parched roots concentrates and burns. Water first, feed second, or feed with the regular watering at half dose: damp soil spreads the salts the way roots can actually take them.