What to Plant in April: Mid-Spring Planting Guide

April is the gardener’s accelerator month. The last frost date is approaching or already past for most US zones, and the race is on to harden off seedlings, direct sow fast-maturing crops, and get summer bulbs into the ground. It is also the month when beginner gardeners make the most common mistake: planting out tender transplants a week too early, only to lose them to a late frost. This guide gives you the definitive zone-by-zone timing so you know exactly what to plant in April — and what to wait on.

April sits at the crossroads of the gardening year. For Zone 3 gardeners, the soil is just thawing and snow is still possible. For Zone 9, the cool-season window is closing fast and summer crops are already underway. The same calendar month means something entirely different depending on where you garden. Use the zone tables below as your primary reference, and always check your local Cooperative Extension Service for the precise last frost date in your county.

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For a complete month-by-month overview, see our Year-Round Planting Guide. If you’re coming from a busy March, our March planting guide covers the cold-hardy crops and seed-starting schedule that set April up for success. For what comes next, jump ahead to the May planting guide.

Last Frost Date: The Number Every April Gardener Needs

The last frost date is the single most important piece of information for April planting decisions. Planting out warm-season crops before this date risks losing transplants to a killing frost overnight. Use the table below as a general reference, then verify with your local Cooperative Extension Service for county-level precision.

A note on soil temperature: Soil temperature is a more reliable trigger for warm-season crops than air temperature. Tomatoes and basil stall below 60°F soil temperature even if frost has passed — they won’t die, but they won’t grow either. A $10 soil thermometer from your local garden center is one of the best investments an April gardener can make. According to Penn State Extension, soil temperature at 2-inch depth is the key measurement for most vegetable crops.

Zone-by-Zone April Planting Guide

Zones 3–4: Indoor Focus, First Outdoor Cold-Hardy Sowings

April in Zones 3 and 4 is primarily an indoor month. Snow is still possible in Zone 3 through early May, and even Zone 4 gardeners should expect one more frost after April 15. The ground may only just be thawing, and soil temperatures are too cold for most crops.

• Direct sow outdoors (cold-hardy): Peas, spinach, lettuce, kale, radishes, and arugula can tolerate light frost. Sow as soon as the soil can be worked — usually mid-to-late April in Zone 4.
• Continue indoors: Tomatoes, peppers, eggplant, cucumbers, squash, and melons should still be under grow lights. Zone 3 gardeners starting tomatoes in early April are on schedule.
• Onions from seed: If you started onion seeds indoors in January or February, they should be 4–6 inches tall. Begin hardening off in late April when temperatures stay above 28°F overnight.

Zones 5–6: Hardening Off and First Root Vegetables

Zone 5 gardeners have a last frost around April 15–30 depending on location. Zone 6 gardeners may see the last frost as early as April 1. This is the most critical zone range for April decision-making — get the hardening-off schedule right and you’ll be weeks ahead of gardeners who skip it.

• Begin hardening off mid-April: Tomatoes, peppers, and cucumbers started indoors need 7–10 days outdoors before transplanting. Start in a sheltered spot.
• Direct sow: Carrots, beets, Swiss chard, and parsnips. Also peas, spinach, lettuce, and kale if not already done.
• Plant onion sets: Zone 5–6 is ideal onion-set territory in April. Plant 1 inch deep, 4 inches apart, pointed end up. University of Minnesota Extension recommends planting onion sets as soon as the soil can be worked in spring.
• Potatoes: Plant seed potatoes 2–4 weeks before the last frost date — a late frost won’t kill them underground. Chit (pre-sprout) in a cool bright room for 2–3 weeks before planting.

Zones 7–8: Full Spring Transition

For Zone 7 and 8 gardeners, April is the most action-packed month of the year. The last frost is behind you or just passing, and the window to get warm-season crops established before summer heat is open but not unlimited.

• Transplant tomatoes and peppers after your confirmed last frost date. Wait until overnight lows are consistently above 50°F — peppers in particular sulk below this threshold even without frost damage.
• Plant summer bulbs: Dahlia tubers, gladiolus corms, canna rhizomes, and caladium tubers all go in during April in Zones 7–8.
• Direct sow warm-season crops late April: Beans, sweetcorn, cucumbers, summer squash, and zucchini once soil exceeds 60°F.
• Succession sow: Lettuce and spinach every 2–3 weeks before heat arrives. These crops bolt once daytime temperatures consistently exceed 80°F.

Zones 9–10: Cool-Season Exit, Heat-Lovers In

By April, cool-season crops are finishing or bolting in Zones 9 and 10. Lettuce, spinach, and peas are going to seed. The task now is to replace them with heat-tolerant warm-season crops and manage the transition before summer arrives.

• Remove bolting cool-season crops and add 2–3 inches of compost before replanting.
• Plant heat-lovers: Sweet potatoes (slips), okra, Southern peas (black-eyed peas), Armenian cucumber, and heat-tolerant basil varieties.
• Mulch heavily: 3–4 inches of organic mulch now will save significant watering effort through May and June.
• Zone 10 note: Stick to heat-adapted varieties bred for tropical conditions. Standard tomato varieties often drop fruit set above 95°F — choose varieties like Heatmaster, Solar Fire, or Celebrity.

How to Harden Off Seedlings: The Most Important April Task

Hardening off is the gradual acclimatisation of indoor seedlings to outdoor conditions. Plants grown under artificial light in consistent indoor temperatures are not ready for wind, UV exposure, temperature swings, or low humidity. Skipping or rushing this process causes transplant shock — leaves turn pale or crispy, growth stalls, and plants may not recover.

Follow this 7–10 day schedule, adjusting if cold snaps are forecast:

Critical hardening-off rules:

• Never leave seedlings out if frost is forecast — check the overnight forecast every day during the hardening period.
• Water more frequently than indoors — small pots in wind dry out in hours on a warm April day.
• If plants wilt badly, bring them in and slow the process down by one stage.
• Wind is more stressful than sun for young seedlings — start in a sheltered spot even on sunny days.

According to Iowa State Extension, even cold-tolerant vegetables like cabbage and broccoli benefit from 4–5 days of hardening before transplanting, particularly if they were grown under grow lights indoors.

Summer Bulbs in April: Dahlias, Gladiolus, Cannas and Begonias

April is the primary planting window for summer-flowering bulbs across most of the US. Get these in the ground now and they’ll reward you from July through the first frost.

Dahlia Tubers

Plant dahlia tubers in Zones 7–10 directly in the ground once the last frost has passed. In Zones 5–6, wait until late April or start tubers in pots indoors 4 weeks before the last frost.

• Plant 4–6 inches deep, eyes facing up.
• Insert the stake before you plant — once the tuber is in the ground, a cane pushed into the soil can spear it. Larger varieties (dinner-plate dahlias) need a stake 4–5 feet tall.
• Pinch out the growing tip at 12–16 inches tall for a bushier plant with more stems. Do not pinch pompon or ball dahlias — they branch naturally.
• Space 18–24 inches apart. Dahlias are heavy feeders — dig in a handful of bone meal at planting time.

Gladiolus Corms

Gladiolus corms planted in April through June give a long succession of cut flowers. Stagger plantings every 2 weeks for blooms from July through September.

• Plant 4–6 inches deep, pointed end up, 6 inches apart.
• Zone 7–10: Gladiolus corms can overwinter in the ground. Zone 5–6: Lift and store after the first hard frost in autumn.
• Stake tall varieties — the 4–foot stems are easily flattened by summer thunderstorms.

Canna Rhizomes

Cannas are tropical plants that need warm soil (above 60°F) to break dormancy.

• Zone 7–10: Plant directly into the ground in April once soil has warmed.
• Zone 5–6: Start rhizomes in pots indoors in April — pot up in multi-purpose compost, keep at 65–70°F, and plant out after the last frost.
• Plant 2–4 inches deep, 18 inches apart. Cannas are vigorous spreaders — give them space.

Begonia Tubers

Tuberous begonias are tender and need a head start indoors in April in most zones.

• Plant hollow-side up in shallow trays of moist peat or coir at 65°F.
• Keep barely moist until shoots emerge — do not overwater at this stage.
• Move to individual pots once shoots are 1 inch tall. Plant out after the last frost in a shaded or semi-shaded position.

Direct Sowing in April: Timing by Crop and Zone

Direct sowing — placing seeds straight into the garden soil rather than transplanting — is faster and often produces better results for root crops that dislike disturbance. April is the main direct-sowing window for many key vegetables.

Beans

Beans are the crop most often planted too early in April. They need soil above 60°F to germinate reliably — below this threshold, seeds rot rather than sprout. Zone 7–8 gardeners can sow late April. Zone 5–6 gardeners should wait for May. Plant 1 inch deep, 4–6 inches apart. According to NC State Extension, bean seed germination drops sharply below 60°F soil temperature.

Sweetcorn

Sweetcorn is wind-pollinated and must be planted in a block rather than rows. A minimum block of 10 x 10 feet (or 4 rows of at least 10 plants) is needed for reliable pollination. Single rows produce ears with missing kernels. Sow 1 inch deep, 9 inches apart in blocks, once soil exceeds 60°F — late April in Zones 7–8, May in cooler zones.

Carrots

Carrots need a fine, stone-free seedbed to grow straight. Prepare the soil by raking thoroughly and removing any stones or clods. Sow thinly in shallow drills, 1/4 inch deep. Do not thin immediately — wait until seedlings are 1–2 inches tall, then thin to 2–3 inches apart. Disturbing the soil during early thinning can cause forking. Zones 5–8 can sow carrots from early-to-mid April.

Beets and Swiss Chard

Beet and Swiss chard “seeds” are actually clusters of 2–3 seeds fused together. Pre-soak overnight before sowing to speed germination. Sow 1/2 inch deep, 3 inches apart, in rows 12 inches apart. Thin to the strongest seedling once established. Beets are cold-tolerant and can be sown from early April in Zones 5–9.

Annual Flowers

• Nasturtiums: Direct sow from mid-April in Zone 6–10. They dislike transplanting. Sow 1/2 inch deep, 10 inches apart. They thrive in poor soil — rich soil produces leaves at the expense of flowers.
• Zinnias: Wait until soil exceeds 65°F and frost risk has passed. Zone 7–8 can sow late April. Zinnias germinate in 5–7 days in warm soil.
• Sunflowers: Sow 1 inch deep once frost risk has passed — Zone 6 late April, Zone 7–8 mid-April.

Pest Management in April

April’s wet, cool weather is ideal for certain pests. Getting ahead of them early prevents major damage later.

Slugs and Snails

Slugs are the number-one April pest in most US gardens. Cool, damp soil and emerging seedlings are exactly what they need. According to Purdue Cooperative Extension, slug populations peak in spring and autumn when temperatures are between 40°F and 65°F.

• Copper tape: Effective barrier around raised beds and containers. Slugs get a mild electric shock from the copper oxide reaction.
• Iron phosphate baits (Sluggo, Escar-Go): Pet and wildlife safe. Apply around vulnerable seedlings. Reapply after rain.
• Torch patrol: Go out at night with a flashlight after rain. Hand-pick slugs and drop in soapy water. Highly effective and costs nothing.

Aphids

Aphids colonise new growth fast — especially brassicas (cabbage, kale, broccoli) and rose buds in April. Check under leaves every few days. First response should always be a strong jet of water to knock them off — aphids rarely climb back up. For heavy infestations, use insecticidal soap spray.

Lily Beetle

Lily beetles (Lilioceris lilii) are vivid red beetles that emerge in April and May specifically to attack lilies and fritillaries. They are now widespread in the northeastern and mid-Atlantic states. Check lily foliage daily from mid-April. The adult beetle, larvae, and eggs are all present — wear gloves when hand-picking as the orange larvae are covered in their own excrement. Oregon State University Extension recommends monitoring from the moment lily shoots emerge in spring.

Lawn Care in April

April is the beginning of the active lawn care season in most of the US. Resist the urge to cut hard and feed heavily in early April — the grass is still waking up.

• Second cut: Set the mower at 3–3.5 inches (never below 3 inches). Cutting too short in spring stresses the grass and opens the sward to weeds.
• Spring fertiliser: Apply a slow-release spring lawn fertiliser once the grass is actively growing — look for green blades extending, not just lying flat. University of Minnesota Extension recommends waiting until mid-April or later in Zone 4–5 to avoid encouraging soft, frost-susceptible growth.
• Overseed bare patches: April is an excellent time to overseed — soil temperatures are rising and spring rainfall helps establishment. Grass seed needs soil above 55°F to germinate. Scratch the surface with a hand rake, broadcast seed, firm down with the back of the rake, and keep moist for 2–3 weeks.
• Dandelions and broad-leaved weeds: Spot treat with a selective broadleaf herbicide or hand-dig before they set seed. A single dandelion can produce 150–200 seeds — acting now prevents a weed explosion in May.

Container Planting in April

April is when window boxes, patio containers, and hanging baskets start to look exciting again. Follow these principles for containers that perform all season.

• Wait for last frost before planting half-hardy annuals: Petunias, pelargoniums (geraniums), lobelia, and impatiens are all frost-tender. Planting them out too early is the most common April gardening mistake.
• Use the thriller/filler/spiller formula: Tall centrepiece (thriller) + mid-height bushy plant (filler) + trailing plant over the edge (spiller). This gives containers a designed, full appearance rather than a random mix.
• Compost: Use a quality peat-free multi-purpose compost with added slow-release fertiliser granules mixed in at planting. This feeds plants for 4–6 months without weekly liquid feeding.
• Watering: Containers dry out fast in April wind — faster than most gardeners expect. Check daily and water when the top 1 inch of compost is dry. Do not let containers dry out completely, as rewetting dry compost can be difficult.
• Cold snaps: Move containers against a house wall or bring indoors if a late frost is forecast — container plants have no soil mass to buffer temperature drops and are more vulnerable than in-ground plants.

For inspiration on what to grow alongside your vegetables, see our companion planting guide. And don’t miss what to plant in spring for the full season overview that places April in context.

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April Planting FAQ

What can I plant outside in April?

In most zones, April is safe for cold-hardy crops outdoors: peas, spinach, lettuce, kale, radishes, carrots, beets, onion sets, and potatoes. Warm-season crops (tomatoes, peppers, beans, corn) go out only after the last frost date, which ranges from early April in Zone 7 to mid-May in Zone 3–4.

When can I plant tomatoes outside in April?

Tomatoes can go out after your last frost date when overnight temperatures consistently stay above 50°F. That’s typically late April in Zone 7, and May in Zone 5–6. Always harden off for 7–10 days before transplanting. Soil temperature should be at least 60°F for good root development.

What flowers can I plant in April?

Summer bulbs — dahlias, gladiolus, cannas, and begonias — go in during April in Zones 7–10. Annual flowers like nasturtiums, sunflowers, and zinnias can be direct sown in Zone 6–8 once frost risk has passed. In containers, wait until after the last frost before planting frost-tender annuals like petunias and lobelia.

Can I plant perennials in April?

Yes. April is an excellent time to plant perennials — the soil is moist and warming, which encourages fast root establishment before summer. Most perennials are cold-hardy and can go in even if light frosts are still possible. Avoid planting tender perennials (salvias, agapanthus) until after the last frost date.

Sources

1. NC State Cooperative Extension — Vegetable Crop Science
2. Penn State Extension — Soil Temperature and Planting Guides
3. Iowa State Extension — Hardening Off Transplants
4. University of Minnesota Extension — Lawn Care and Vegetable Gardening
5. Purdue Cooperative Extension — Slug Management
6. Oregon State University Extension — Lily Beetle Monitoring