How Many Seeds Should You Use? A Fun & Easy Guide!
So, you’ve nurtured your seedlings, watched them grow, and now it’s time to start fresh by planting new seeds. But then comes the big question—how many seeds should you use per Rockwool cube? 🤔
Don’t worry—I’ve got you covered! Whether you’re growing lettuce, herbs, leafy greens, or fruiting veggies in your Tower Garden, this guide will help you plant with confidence.
Why Seed Count Matters
Unlike traditional gardening, where you sprinkle a whole row of seeds and thin them out later, Tower Garden growing is all about efficiency. We typically use one seed per Rockwool cube, which means a good-quality seed is a must—because if it doesn’t germinate, you’ll notice right away!
Alright, let’s dig in and get seeding! 🌱👇
🥬 Lettuce: Tiny Seeds, Big Results
Can one tiny lettuce seed really grow into a full head of lettuce?
Yep! It’s pretty amazing how something so small can turn into a big, beautiful, delicious leafy green. But not all lettuce types are created equal—so here’s how many seeds to use for each variety:
Head Lettuce (Bibb, Iceberg, Buttercrunch, etc.)
🥬 Use 1 seed per Rockwool cube
📌 Why? These lettuces grow into tight, compact heads, and multiple seeds in one cube will result in overcrowding. One seed is all you need!
Fun Fact: A friend of mine once grew Iceberg lettuce in her Tower Garden, and it was almost as green as Bibb! Who knew?!
Leaf Lettuce (Romaine, Green Leaf, Red Leaf, etc.)
🥬 Use 1 seed per Rockwool cube in cooler months
☀️ Use 2-3 seeds in summer
📌 Why? Lettuce is a cool-weather crop, and in the heat, it tends to bolt (go to seed). Planting a few extras means you’ll still get a good harvest before it bolts. More lettuce, faster! WIN-WIN!
Spring Mix & Mesclun Lettuce
🥬 Use 6-8 seeds per cube (or up to 12 if you love baby greens!)
📌 Why? These lettuces are meant to be cut and regrown, so planting more seeds per cube gives you a fuller, faster harvest.
🌿 Herbs: The More, The Merrier (Sometimes!)
Chives
🌿 Use 20+ seeds per cube (but no more than 50!)
📌 Why? Chives grow in clumps, so the more seeds you use, the bigger the bunch.
All Other Herbs (Basil, Cilantro, Oregano, Thyme, etc.)
🌿 Use 6-8 seeds per cube
📌 Why? This gives you a strong, healthy plant without overcrowding.
🥦 Leafy Greens: The Powerhouse Crops
Kale, Chard, Collards, Mustard Greens, etc.
🥬 Use 1 seed per cube (or 2 if you want extra greens!)
📌 Heads up! Chard grows massive stalks—if left too long, it can actually break your Tower Garden shower cap (yes, I learned this the hard way! 😆).
Spinach
🥬 Use 2-3 seeds per cube
📌 Why? Spinach is a little trickier to germinate, so planting a couple of extras increases your chances of success.
Arugula
🥬 Use 6-8 seeds per cube
📌 Why? Arugula grows fast, and more seeds mean a fuller harvest in a shorter time.
🍅 Fruiting Vegetables: Size Matters!
Beans, Peas, Cucumbers, Melons
🍃 Use 1-2 seeds per cube
📌 Why? These plants have smaller stems and leaves, and a single plant won’t produce a ton—so having two plants in one Rockwool cube can boost your harvest!
⚠️ Tip: Be extra careful when pruning and training bean plants—you don’t want to accidentally cut too many leaves off one plant while they’re growing together!
Squash, Tomatoes, Peppers, Eggplant, Okra
🍅 Use 1 seed per cube
📌 Why? These plants get big, leafy, and wild—too many in one cube leads to overcrowding, airflow issues, and even fungus problems. No bueno.
🍓 Strawberries: Just Don’t.
🚫 Don’t start strawberries from seed in your Tower Garden.
📌 Why? They grow slowly and won’t produce well until their second year. That’s a lot of time and space wasted for very little reward. Instead, use strawberry starts!
🔎 Final Thoughts: Quality Seeds Matter!
Since we often plant just one seed per Rockwool cube, good-quality seeds are essential. If you’re unsure where to get them, check out my favorite seed suppliers [here]!
Having trouble getting your seeds to germinate? 🌱 Check out my troubleshooting guide: "Why Didn’t My Seeds Germinate?"
🚀 Now it’s your turn! What’s your favorite thing to grow in your Tower Garden? Drop a comment below! 🌿👇