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All Sweet Watermelon

All Sweet · Cucurbitaceae

Large striped heirloom watermelon with bright red flesh, strong sweetness, and a comparatively tough rind that helps protect fruit in the field. Produces big elongated melons on vigorous vines. Key facts: 90–95 days to maturity, 8+ hours of sun, 36–48 " spacing. Not recommended for containers.

Updated April 19, 2026 · Backed by 4 cited sources
Overview

At a Glance

The essentials first: timing, light, spacing, seed-starting, container fit, and overall size.

Days to maturity
90–95 days
Sun
8+ hours
Full Sun, 8 10+ Hours
Spacing
36–48 "
between plants
Seed start
2–4 weeks
before transplant
Container
Not recommended
Needs 20+ gal if attempted
Height
0.5–1.5 ft
at maturity
Planting window

Zone Planting Guide

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This card updates instantly with viability, frost timing, and any planting notes for your selected zone.

Care

Growing Guide

Everything in one place: seed starting, transplant timing, watering, soil, and structural support.

Seed starting
Germination
Time5–10 days
Optimal temperature85°F
Seed depth1"
Moving outdoors
Transplanting
Minimum soil temp70°F
Harden off7 days
Moisture
Watering
Weekly1–2 "
NeedsConsistent
Drip or soaker hose
Root zone
Soil
pH range6–6.5
PreferredLight, Fertile, Well Drained Sandy Loam
Watermelon - All Sweet seeds

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Watermelon - All Sweet seeds

They grow on a long vine, so make sure to give them plenty of space to roam around.

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A-Frame Vegetable Trellis (50"x50")

Folds flat for storage, fits inside standard raised beds. Works for cucumbers, squash, beans, peas, and small melons.

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Resilience

Plant Health

Stress tolerance, resistance notes, and the most common problems to watch for as plants mature.

Tolerance
Heat: Moderate Cold: Low Drought: Moderate

Common Issues

Poor Fruit Set

Cause: Low bee activity or extreme weather during bloom reduces pollination.

Prevention: Protect pollinators and hand-pollinate if necessary.

Sunburn And Cracking

Cause: Irregular moisture or exposed fruit in extreme heat can hurt rind quality.

Prevention: Maintain steady moisture and avoid excessive vine pruning that exposes fruit.

Feeding & picking

Nutrition & Harvest

How hungry the plant is, what ripe harvest looks like, and how long the crop keeps after picking.

Feeding
Nutrition
Feeding intensityHeavy feeder
RecipesRoot Drench, Worm Castings Topdress, Compost Tea
Timing
Harvest

Harvest when the tendril nearest the fruit stem turns brown and dry, the rind dulls, and the ground spot turns creamy yellow.

Expected yield25–75 lbs/plant
Storage10 days — Store whole fruit in a cool room for several days; refrigerate after cutting.

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Espoma Tomato-Tone (4lb)

The fertilizer extension agents recommend. 3-4-6 NPK with 8% calcium to prevent blossom end rot. From the brand that's been in business since 1929.

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Plant relationships

Companion Planting

Helpful neighbors can support growth or deter pests. Keep antagonistic plants separated to reduce stress and competition.

What you'll need

Growing Supplies

Based on All Sweet's growth profile -- recommendations matched to this variety's specific requirements.

Drip irrigation / soaker hose kit

Every gardener benefits from putting water at the root zone instead of on the leaves, because drip and soaker systems reduce foliar disease pressure by limiting leaf wetness and soil splash. A quality kit should include a backflow preventer, filter, pressure reducer, and UV-resistant tubing.

Source: Iowa State University Extension; Colorado State University Extension; UMass Extension

Soil test kit

A soil test gives a baseline for pH and nutrient status so gardeners can add only what the soil actually needs. Prioritize a mail-in or lab-affiliated kit whenever possible because extension guidance notes that laboratory testing is more accurate than instant readers.

Source: University of Maryland Extension; Purdue Extension; Montana State University Extension

Quality bypass pruners

Extension guidance favors bypass designs because they make cleaner, closer cuts on living tissue than anvil types. Look for hardened steel blades that can be sharpened, a comfortable grip, and a cutting capacity matched to real home-garden stems.

Source: University of New Hampshire Extension; Iowa State University Extension; Purdue University Extension

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Research

Sources

Reference material and extension guidance used to build this growing guide.

seed_catalog SeedsNowuniversity University of Georgia Extensionuniversity University of Minnesota Extensioninference All Sweet yield range and storage inferred from large heirloom watermelon extension guidance and catalog fruit-size description.
Internal links

All Sweet Watermelon Planting Dates by Zone

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