How Many Watermelon Seeds Per Hole? | Planting Numbers

For hill planting, sow 6–8 seeds per hill and thin to 3–4 of the strongest plants; for row planting, place 2–3 seeds per hole.

You picture a summer watermelon harvest, so you drop a single seed into each hole, thinking one plant per spot is the way to go. Or maybe you crowd every seed from the packet into one mound, hoping for a jungle of melons. Both approaches skip a key piece of the puzzle.

The honest answer depends on your planting method. Hills and rows have different spacing rules, and the number of seeds you start with directly affects how many healthy plants you end up with. This article covers the standard recommendations from university extension services and seed companies so you can sow with confidence.

Seeds Per Hole And Per Hill: The Core Numbers

If you are using a row system, place 2–3 seeds per hole. Iowa State University Extension recommends this approach for row planting, with a depth of 1 inch. After the seeds germinate, you will thin each hole to the single strongest seedling.

For hill planting (raised mounds of soil), the numbers go up. Sow 6–8 seeds per hill. Seed Savers Exchange and Urban Farmer Seeds both give this range. The idea is to account for lower germination rates in cooler soil and to give yourself plenty of candidates for thinning. Later, remove all but 3–4 of the most vigorous plants per hill.

A few sources (like Eden Brothers) suggest 4–6 seeds per mound, so the exact count varies slightly. The common thread is that you always seed more than you want to keep.

Why The Number Matters For Your Watermelon Harvest

Sowing extra seeds feels wasteful, but skipping this step often leads to bare patches. Watermelon seeds have a germination rate that is rarely 100% — soil temperature, moisture, and seed age all play a role. Starting a few extra seeds per hole or hill acts as insurance.

• Competition management: Twelve watermelon vines from twelve seeds in one hill would crowd each other out. By starting six to eight and thinning to three or four, you let the strongest plants have enough root space and sunlight.
• Soil temperature buffer: If the soil is barely above 70°F, germination can be spotty. Extra seeds improve the odds that enough seedlings emerge to give you a good selection for thinning.
• Variety sizing: Larger watermelon varieties (like Charleston Gray) need more room between hills — at least 6 to 12 feet apart. More seeds per hill does not mean you can squeeze the spacing; the thinning step removes the extras so the survivors have room to spread.
• Pest and disease risk: If cutworms or damping-off take out a few seedlings, the extras mean you will still have enough plants without reseeding.
• Personal preference: Some gardeners prefer to start seeds indoors (up to four weeks before the last frost) and transplant two or three strong seedlings per hill. In that case, you skip the extra seeds and plant only what you need.

Thinning is not cruel — it is the most reliable way to get healthy, productive watermelon plants. Each hill should end up with three or four evenly spaced vines that have room to roam.

Step-By-Step: How To Plant Watermelon Seeds Correctly

Start by preparing the soil after the last frost date. Build hills about 12 inches tall and 24 inches across, spaced at least 6 feet apart for standard varieties. For smaller types like Sugar Baby, 4 feet between hills may be enough.

Make a shallow trench or dimple in the top of each hill, about 1/2 to 1 inch deep. Drop in your seeds — aim for that 6–8 range. Cover with soil and press gently. Then water the seeds into the hills, keeping the soil consistently moist until germination. The Iowa State Extension guide suggests using plant 4 or 5 seeds per hill and later removing all but two or three healthy, well-spaced plants. Their numbers sit at the lower end of the range, which works well for gardeners who start seeds indoors or have high-germination seed lots.

After the seedlings have two or three true leaves, thin by cutting the weakest ones at soil level. Do not pull them up — pulling can disturb the roots of the keepers.

Here is a quick reference table for the main planting factors:

Whichever number you choose, the depth stays mostly consistent: 1 inch for rows, 1/2 to 1 inch for hills. Deeper planting can delay emergence, especially in heavy soil.

Common Mistakes To Avoid When Sowing Watermelon Seeds

New growers often treat watermelon like other vine crops, and a few habits can sabotage the harvest before it starts. Here are the most frequent errors.

1. Planting too deep. Watermelon seeds need warmth to germinate. Burying them deeper than 1 inch in cool soil can prevent sprouting entirely. Stick to 1/2 to 1 inch depending on your method.
2. Skipping the frost check. Direct-seeding before the soil has warmed to at least 70°F leads to rot. Wait until all danger of frost has passed and the soil temperature is reliably warm. Starting seeds indoors can buy you time in short-season climates.
3. Overcrowding after thinning. Even if you start eight seeds per hill, thinning to five plants is not enough. Three or four vines per hill gives each one adequate room. With too many vines, fruit size and sweetness can suffer.
4. Planting hills too close together. Watermelon vines can sprawl 10 to 15 feet. If your hills are only 3 feet apart, the vines will tangle and reduce airflow, raising the risk of powdery mildew. Give them the full 6 to 12 feet.

One more tip: water your hills deeply after planting, then keep the soil consistently moist until the seeds germinate. Wetting the soil surface every day is not enough — aim water at the root zone of each hill.

Temperature And Timing: When To Direct-Seed Watermelons

Watermelons are heat-loving crops. Direct-seeding into cold soil is the fastest way to lose seeds to rot or fungal disease. The Texas A&M AgriLife Extension recommends waiting until the soil seed zone temperature exceeds 70°F. You can use a soil thermometer at a depth of 2 inches to check. If you do not have a thermometer, a rule of thumb is to plant one week after the last frost date when daytime highs are consistently above 80°F.

Soil seed zone temperature exceeds that threshold, according to the Texas A&M guide, and you can direct-seed at a rate of 300 to 600 seeds per 100 feet of row for commercial plantings. For home gardens, you will rarely need that many, but the principle holds: warm soil is non-negotiable.

Here is a quick-reference table for the key temperature and timing factors:

If you live in a cool northern climate, consider using black plastic mulch to warm the soil a few degrees. Row covers can also help trap heat during the first few weeks after seeding. Just remove the covers when flowers appear so bees can pollinate.

The Bottom Line

Sowing the right number of watermelon seeds per hole or hill comes down to two simple rules: for rows, drop 2–3 seeds per hole; for hills, drop 6–8 and thin to 3–4 of the strongest. The extra seeds act as a buffer against uneven germination and give you the best chance of a full stand of healthy vines. Warm soil, proper depth, and generous spacing complete the picture.

Your local extension office or a seasoned gardening neighbor can help you fine-tune the numbers for your specific variety (like Sugar Baby or Crimson Sweet) and your soil type — especially if you are working with a smaller garden bed where every hill counts.