Best Fertilizer for Kale
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GardenSays
Kale plants may need light feeding depending on your soil — we don't have a plant-level precise rate for this crop yet, so follow a soil test or your fertilizer's label rate rather than a guessed number.
- Fertilizer needed?
- Depends on soil test
- Precise rate
- Not yet sourced
UMN's growing guide ties phosphorus and potassium to your own soil test. It does give one precise application: about 1/2 cup of 46-0-0 (or 1 cup of 27-3-3, or 3 1/2 cups of 10-3-1) per 100 ft of row, applied alongside the row once plants are about 4 inches tall — but it states no repeat interval, so we show this as a one-time note rather than inventing a recurring schedule.
- Don't use a 'Weed and Feed' product — the herbicide in it will kill vegetable plants.
Calculated result · 1 verified source · Checked 2026-07-18 · How we decide
Why
Without a source-verified per-plant dosage, the safest move is a soil test (or your fertilizer product's own label rate) rather than a generic number we can't stand behind.
- UMN frames pre-plant phosphorus and potassium as soil-test-first, but does give one precise, timed sidedress application — just not a repeat interval.
- Every number on GardenSays is sourced or labeled an estimate — without a plant-level dosage source, we show guidance instead of a guessed figure.
When this doesn't apply
How this was calculated
- 1. Feeding profile
Kale: UMN frames pre-plant phosphorus and potassium as soil-test-first, but does give one precise, timed sidedress application — just not a repeat interval.
- 2. Need assessment
UMN's growing guide ties phosphorus and potassium to your own soil test. It does give one precise application: about 1/2 cup of 46-0-0 (or 1 cup of 27-3-3, or 3 1/2 cups of 10-3-1) per 100 ft of row, applied alongside the row once plants are about 4 inches tall — but it states no repeat interval, so we show this as a one-time note rather than inventing a recurring schedule.
Data sources
- University of Minnesota Extension — Growing collards and kale in home gardens — Apply phosphorus (P) and potassium (K) according to soil test recommendations; many Minnesota soils have enough phosphorus. When the plants are about four inches tall, apply fertilizer alongside the row of plants at a rate of one-half cup of 46-0-0, or one cup of 27-3-3, or 3-1/2 cups 10-3-1 for each 100 feet of row. Do not use any fertilizer containing a weed killer ("Weed and Feed"). (checked 2026-07-18)
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People also ask
How often should I water kale?
Water deeply 2× per week, about 0.7 gallons per plant each time. Calculate yours →