How Many Seeds Should You Use? A Fun & Easy Guide!
This article is part of our complete collection of guides to help you choose crops, start seeds successfully and grow strong, healthy seedlings.
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How many seeds should you plant per hole or rockwool cube? The answer depends on what you're growing. Some plants need just one seed, while crops such as herbs, spinach and baby greens grow better when several seeds are planted together.
If you're starting seeds for a Tower Garden, hydroponic system or traditional garden, this guide gives you a simple starting point for lettuce, herbs, leafy greens, fruiting vegetables and more.
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Find the crop you're planting and see how many seeds to use.
How Many Seeds Should I Plant Per Hole or Rockwool Cube?
Here's the quick answer. These are the seed counts we use as a starting point when growing in rockwool.
| Crop | Seeds Per Hole / Rockwool Cube |
|---|---|
| Head Lettuce | 1 seed |
| Leaf Lettuce | 1 seed in cooler weather; 2–3 in summer |
| Spring / Mesclun Mix | 6–8 seeds; up to 12 for baby greens |
| Chives | 20+ seeds |
| Most Other Herbs | 6–8 seeds |
| Kale, Chard, Collards & Mustard Greens | 1–2 seeds |
| Spinach | 5–6 seeds |
| Arugula | 6–8 seeds |
| Beans, Peas, Cucumbers & Melons | 1–2 seeds |
| Squash, Tomatoes, Peppers, Eggplant & Okra | 1 seed |
Why Isn't the Number the Same for Every Plant?
The goal isn't simply to make sure something germinates. Seed count also depends on how the crop grows after germination. A tomato can become a large plant from one seed, while chives naturally grow as a cluster and need many seeds to create a full bunch.
How Many Lettuce Seeds Should You Plant Per Hole?
Head Lettuce
Use 1 seed per rockwool cubeBibb, iceberg, butterhead and other head lettuces need room to develop. Multiple plants in one cube can compete for space as the heads become larger.
Leaf Lettuce
Use 1 seed in cooler weather; 2–3 seeds in summerDuring hot weather, loose-leaf lettuce has a shorter productive window before heat encourages bolting. Starting a few plants together can give you more leaves to harvest sooner.
Spring Mix & Mesclun
Use 6–8 seeds per cubeFor baby-green-style harvesting, you can use up to about 12 seeds per cube to create a fuller cluster of young leaves.
Growing lettuce in a Tower Garden? See our complete Tower Garden lettuce growing guide .
How Many Herb Seeds Should You Plant Per Hole?
Chives
Use 20+ seeds per cubeChives naturally grow in clumps, so multiple seeds create the fuller bunch you want. You can plant more, but we generally wouldn't exceed about 50 seeds in a single cube.
Basil, Cilantro, Parsley, Dill & Other Herbs
Use 6–8 seeds per cubePlanting several seeds together creates a fuller herb planting while still giving the seedlings room to grow.
How Many Leafy Green Seeds Should You Plant?
Kale, Chard, Collards & Mustard Greens
Use 1–2 seeds per cubeThese crops can become large plants, so they don't need to be planted densely. Chard in particular can become surprisingly large in a Tower Garden.
Spinach
Use 5–6 seeds per cubeSpinach can be more challenging to germinate consistently, so we plant several seeds together to improve the chances of establishing a useful cluster.
Arugula
Use 6–8 seeds per cubeArugula grows quickly and works well as a cluster, giving you a fuller harvest from each growing position.
How Many Fruiting Vegetable Seeds Should You Plant?
Beans, Peas, Cucumbers & Melons
Use 1–2 seeds per cubeOne or two plants can share the same starting cube. If both seedlings grow, remember that each plant will still need enough light, airflow and room as it matures.
Squash, Tomatoes, Peppers, Eggplant & Okra
Use 1 seed per cubeThese crops develop into much larger plants. Starting multiple plants in one cube creates unnecessary competition and crowding, so one healthy seedling is all you need.
Should You Start Strawberries From Seed?
Strawberries can be grown from seed, but they're much slower to establish than many of the crops on this list and aren't usually our preferred way to start strawberries for a Tower Garden.
If your goal is to begin harvesting sooner, established strawberry plants or starts are the more practical option.
If you're planning to grow strawberries in your tower, see our guide to growing strawberries in a Tower Garden .
Seed Count Is Only Part of Successful Germination
Even when you plant the right number of seeds, germination still depends on factors such as moisture, temperature and seed quality.
If your seeds aren't sprouting, see our Seeds Not Germinating? 5 Common Reasons Why troubleshooting guide.
Explore More Seed & Seedling Guides
Continue learning with these helpful guides, or return to the complete Seeds & Seedlings Learning Center.
Plan Your Garden
Choose crops based on season, plant size, harvest timing, pollination and your growing goals.
Plan Your Garden →Seeds Not Germinating?
Troubleshoot poor germination caused by moisture, temperature, seed quality and other common problems.
Fix Germination Problems →Beginner's Guide to Seed Saving
Learn which seeds can be saved, when to collect them and how to store them for another growing season.
Start Saving Seeds →Growing Strong Seedlings
Learn how to take newly germinated seeds through the next stage and prepare healthy seedlings for your Tower Garden.
Explore Seedling Guides →
