April garden tasks: Pacific Northwest
April in the Pacific Northwest brings the first reliable dry spells in Western Oregon and Washington, though the reliable dry period doesn't fully arrive until June. Average rainfall in Portland is 3.4 inches in April versus 1.0 inch in July -- the drying trend begins, but it's not dry yet. That.
—- title: "April garden tasks: Pacific Northwest" slug: april-garden-tasks-pacific-northwest hub: care category: "Monthly tasks" description: "April garden tasks for the Pacific Northwest — succession planting, warm-season crop starts, blueberry and fruit tree care, and managing the transition from wet spring to dry summer." date: 2026-06-10 updated: 2026-06-10 author: "Thomas A." reading_time: 7 zones_min: 7 zones_max: 9 —-
April in the Pacific Northwest brings the first reliable dry spells in Western Oregon and Washington, though the reliable dry period doesn't fully arrive until June. Average rainfall in Portland is 3.4 inches in April versus 1.0 inch in July — the drying trend begins, but it's not dry yet. That transition matters for how you manage soil, irrigation, and disease.
Per Oregon State Extension, average last frost dates: Portland March 21, Seattle March 24, Willamette Valley lowlands March 20. By April 1, most PNW lowland gardens are frost-free, though late frosts are possible through April in inland valleys and higher elevations.
Cool-season crops at peak production
April is the prime cool-season growing month in the PNW. Per WSU Extension, these crops are performing best now:
- Overwintered kale, leeks, and spinach from fall planting are ready for heavy harvest
- Direct-sown spring peas are up and growing vigorously
- Lettuce and salad greens planted in March are approaching harvest size
April succession sowing (cool-season):
- Sow lettuce every 2—3 weeks for continuous harvest; April sowings produce June—July harvests before heat ends the season
- Succession sow spinach, radishes, and cilantro through mid-April; heat will bolt them by May—June in most of the PNW
- Sow beets and carrots for July harvest; these take 60—75 days from sowing
Warm-season crop indoor starts
Per Oregon State Extension, start these indoors in April for May/June transplanting:
- Basil: start April 1—15 for transplanting after May 15
- Cucumber, squash: start April 15 for transplanting by mid-May (these grow fast and don't need a head start before April)
- Melons: in warm PNW microclimates (eastern slopes, warm valleys), start melons indoors April 1 for transplanting mid-May; choose short-season varieties ('Earli-Dew', 'Collective Farm Woman')
Tomatoes and peppers started in March should be under lights at appropriate size for May transplanting.
Blueberry care
Per WSU Extension, April is the prime time for blueberry management in the PNW:
- Fertilize: apply ammonium sulfate when new growth begins (typically April 1—15 in zone 8b); ammonium sulfate acidifies soil and provides the ammonium form of nitrogen preferred by blueberries; use 0.5 oz ammonium sulfate per established plant per year of age, up to 1 lb per plant maximum
- Mulch: apply 3—4 inches of sawdust, bark, or wood chips around blueberries to maintain soil moisture and acidity; do not use hay or straw (raises pH over time)
- Mummy berry: per WSU Extension, mummy berry (Monilinia vaccinii-corymbosi) is the primary blueberry disease in the PNW; remove and discard any mummified fruit from last season before new growth; apply fungicide at bud break if disease was present last year
Fruit tree management
Per Oregon State Extension, April apple and pear management:
- Fire blight monitoring: check for blossom blight (wilted, blackened blossoms that look water-soaked) during and after bloom; remove affected wood 12 inches below the visible infection, disinfecting tools between cuts
- Codling moth: adults begin flying when apple trees are in full bloom; place pheromone traps in trees to monitor; first spray timing (kaolin clay, spinosad, or reduced-risk pesticide) is triggered by trap catch data
- Aphid monitoring: woolly apple aphid and green apple aphid both begin in April; per Oregon State, avoid broad-spectrum insecticides that kill beneficial insects; use insecticidal soap or neem oil for significant infestations only
Slug monitoring (ongoing)
Per Oregon State Extension, slug pressure remains high in April and continues until soils dry in June. Reapply iron phosphate slug bait (Sluggo (iron phosphate slug bait)) every 2—3 weeks or after heavy rain. This is not optional in PNW gardens — transplants set out in April without bait protection will be stripped overnight.
Lawn care
Per WSU Extension, April lawn tasks in the PNW:
- Overseed bare spots: April is the second-best window for cool-season turf seeding; keep seeded areas moist for 3 weeks until germination
- Fertilize cool-season lawns: apply a slow-release nitrogen fertilizer (1 lb N per 1,000 sq ft) in April for the spring growth push; follow with a second application in September for the fall flush
- Pre-emergent: Oregon and Washington have less crabgrass pressure than eastern states, but annual bluegrass (Poa annua) is the primary weed in PNW lawns; pre-emergent application in early spring reduces annual bluegrass pressure
Soil amendment
Per Oregon State Extension, with April's reduced rainfall, it becomes more practical to incorporate organic matter. Add 2—3 inches of compost to beds that haven't been amended recently. The soil is workable more reliably in April than in the saturated March conditions.
Common mistakes
| Mistake | Consequence | Correct approach |
|---|---|---|
| Transplanting tomatoes in April | Cold soil and cool nights stall growth or cause root disease | Wait until mid-May when soil reaches 60°F |
| Ignoring slug control at transplant time | Overnight destruction of seedlings | Apply iron phosphate bait 24—48 hours before transplanting |
| Not protecting blueberries from birds during bloom/fruit set | Significant berry loss | Install bird netting before berries form |
Frequently asked questions
When should I transplant kale and cabbage starts outdoors in the PNW? Per WSU Extension, kale, cabbage, and broccoli transplants can go outdoors in April once they've been hardened off. These crops tolerate frost to 25—28°F. floating row cover provides additional protection for early April transplants if frost threatens.
Can I start fall-harvested crops in April? Yes. Per Oregon State Extension, brassicas (broccoli, cabbage, Brussels sprouts) intended for fall harvest should be started indoors in April for June transplanting. June transplants produce fall harvest; later starts may not mature before frost in zones 7—8.
Recommended gear: Best iron phosphate slug bait: Sluggo vs Slug Magic vs generic — our buyer's guide covering picks for every budget, ranked by Extension publication consensus and personal use.
Sources
- Oregon State Extension — Home Vegetable Gardening
- WSU Extension — Gardening in Western Washington
- Oregon State Extension — Fire Blight Management
- Oregon State Extension — Managing Slugs