Watering & fertilizer quick reference
Print this. Tape it near the hose timer. Ignore it at your peril. Numbers assume raised beds or well-amended in-ground soil in Kennewick heat—adjust for sandier spots and 100°F weeks.
How to use this without being dense: “1–1.5 inches of water per week” means total from irrigation (rain almost never helps in summer).
Stick a tuna can under the drip/emitter pattern or check soil 4–6 inches down with your finger.
If it’s dry as a bag of flour, water. If it’s muddy, stop. This is not calculus.
Sunlight, soil & spacing
| Crop | Sun | Soil pH target | Soil texture notes | Spacing (approx.) |
|---|---|---|---|---|
| Sweet corn | Full sun (8+ hrs) | 6.0–6.8 | Deep, fertile, moisture-retentive; amend Basin sand with compost | 8–12" in-row; 30–36" rows; plant in blocks |
| Bell peppers | Full sun | 6.0–7.0 | Well-drained, high organic matter; avoid cold wet soil | 18–24" plants; 24–36" rows |
| Jalapeños | Full sun | 6.0–7.0 | Same as bells; heat-tolerant once established | 18–24" plants |
| Basil | Full sun (light afternoon shade OK in extreme heat) | 6.0–7.0 | Rich, well-drained; hates soggy feet | 10–12" plants |
| Zucchini | Full sun | 6.0–7.5 | Fertile, well-drained; loves compost | 24–36" plants (bush); more for vining |
| Onions | Full sun | 6.0–7.0 | Loose, well-drained; rocks = weird bulbs | 3–4" plants; 12–18" rows |
Watering schedules (Kennewick summer baseline)
| Crop | Establishment (first 2–3 wks) | Mid-season (typical Jul heat) | Critical timing | Method notes |
|---|---|---|---|---|
| Sweet corn | Keep seedbed moist until up; light frequent if surface crusts | ~1–1.5"+ / week; deep soaks 1–2× weekly | Tassel & silk: never drought here | Drip or furrow-style deep water; mulch between rows |
| Bell peppers | Even moisture; no dry-out or flood | ~1–1.5" / week; more in extreme heat | Flowering & fruit set: consistency > volume spikes | Drip at base; wet leaves invite disease theater |
| Jalapeños | Even moisture | ~1–1.25" / week; slightly less needy than bells once rooted | Fruit swell: keep even to avoid blossom-end issues | Drip preferred; mulch always |
| Basil | Never let pot/bed go bone dry | Frequent lighter irrigations; soil moist not swampy | Heat waves: check daily in containers | Morning water; avoid soaking leaves overnight |
| Zucchini | Moist seedbed; careful with transplants | ~1–2" / week; deep soaks at root zone | Fruiting: uneven water = bitter/odd fruit & rot risk | Water soil, not the whole leaf canopy if possible |
| Onions | Steady moisture for shallow roots | ~1" / week equivalent; more on sand | Bulbing: even water; reduce when tops fall | Drip ideal; stop heavy water at cure stage |
Fertilizer cheat sheet
| Crop | At planting | Side-dress / feed schedule | What to avoid |
|---|---|---|---|
| Sweet corn | Compost + balanced fertilizer; nitrogen-forward soils help | Side-dress N when plants ~12" and again at knee-high / pre-tassel | Starving N (yellow lower leaves, tiny ears); overdoing late N less critical than missing mid-season |
| Bell peppers | Compost; moderate starter; phosphorus for rooting if soil test low | Light feed every 3–4 weeks after fruit set; or slow-release at plant | Heavy nitrogen early (all leaves, no fruit); drought + hot fertilizer burn |
| Jalapeños | Same as bells | Similar; slightly less heavy feeding often still yields well | Same blossom-drop triggers: cold nights, heat stress, wild water swings |
| Basil | Rich compost; light balanced fertilizer | Light liquid feed every 2–3 weeks if growth stalls | Salt burn; soggy overfertilized pots that smell like regret |
| Zucchini | Heavy compost; balanced fertilizer in the planting hole zone | Side-dress when vines run / first fruits set | Planting in pure sand with zero organic matter (welcome to zero zucchini) |
| Onions | Compost; nitrogen available early for leaf growth | Side-dress N 3–4 weeks after planting and again mid-growth; ease off as bulbs swell | Fresh hot manure at planting (weird growth / disease risk); late heavy N delaying bulb maturity |
Basin soil reality check
Columbia Basin soils often lean sandy or silty (loess), drain fast, and run alkaline. That means nutrients can wash through, iron can lock up, and organic matter disappears if you never add any.
- Compost annually — 1–2 inches worked into beds is the boring miracle cure.
- Mulch — wood chips, straw, or shredded leaves. Keep mulch off stems a bit.
- Soil test every few years — if pH is high, elemental sulfur + organic matter help over time; don’t dump random acids like a medieval alchemist.
- Micronutrients — yellowing between veins on new leaves in high pH soils can be iron chlorosis; fix drainage/pH/organic matter, not just more mystery spray.
Full crop write-ups: Corn · Bell peppers · Jalapeños · Basil · Zucchini · Onions