How to Grow Microgreens in Mason Jars: A Windowsill Garden Anyone Can Start
🌱 TL;DR — Key Takeaways
- Microgreens contain up to 40x more nutrients than mature plants (USDA research)
- Ready to harvest in just 7–14 days from soaking
- All you need: mason jar, sprouting lid, seeds, water, and a sunny windowsill
- Best beginner seeds: broccoli, radish, alfalfa, and mung bean
- Avoid nightshade seeds (tomato, pepper, eggplant) — they produce toxic alkaloids as sprouts
If you have a sunny windowsill, a mason jar, and about ten minutes, you can grow your own microgreens at home. These tiny powerhouses of nutrition are one of the easiest things you can grow — no garden bed required, no special equipment, and they are ready to eat in as little as 7 to 14 days. I keep three jars rotating on my kitchen windowsill year-round, and it is one of the simplest ways I have found to add fresh homegrown food to every meal.
What Are Microgreens and Why Are They So Nutritious?
Microgreens are young seedlings harvested just after they develop their first true leaves — and USDA research shows they can contain up to 40 times more nutrients than mature plants. They are not the same as sprouts: microgreens grow in light and develop tiny leaves, while sprouts germinate in water in the dark. A small handful of broccoli microgreens packs a serious punch of vitamins C, E, and K.
What Supplies Do You Need?
- Wide-mouth mason jars (pint or quart size)
- Sprouting lids or cheesecloth secured with rubber bands
- Organic sprouting seeds (broccoli, radish, alfalfa, clover, or mung bean are beginner-friendly)
- Fresh water
- A bowl or dish rack for draining
- A sunny windowsill or grow light
Important: Always use seeds labeled specifically for sprouting or microgreens. Regular garden seeds may be treated with chemicals not safe to eat.
How Do You Grow Microgreens Step by Step?
The entire process takes 7–14 days and requires only minutes of daily attention — here is exactly how to do it.
Step 1 — Soak: Add 1 to 2 tablespoons of seeds to your jar, cover with a few inches of cool water, and soak 8 to 12 hours (overnight is easiest).
Step 2 — Drain and rinse: Drain through your sprouting lid, rinse with fresh water, and prop the jar upside-down at an angle so water drips out and air circulates. This prevents mold.
Step 3 — Keep them dark: For the first 3 to 4 days, keep the jar in a cupboard or closet. Darkness encourages strong roots and tall stems. Continue rinsing twice daily.
Step 4 — Move to light: When sprouts are about an inch tall with tiny yellow leaves, move the jar to a bright windowsill. Within a day or two, leaves turn vibrant green through photosynthesis.
Step 5 — Harvest: When first true leaves appear (7–14 days from soaking), snip with clean scissors or pull gently. Rinse, pat dry, and enjoy immediately.
Which Seeds Are Best for Mason Jar Microgreens?
| Category | Seeds | Flavor Profile | Days to Harvest |
|---|---|---|---|
| Easiest for beginners | Alfalfa, mung bean, broccoli | Mild, slightly nutty | 5–7 days |
| Bold flavor | Radish, mustard, arugula | Peppery, spicy | 7–10 days |
| Nutty and satisfying | Sunflower, pea shoots | Sweet, crunchy | 8–12 days |
| Avoid — toxic as sprouts | Tomato, pepper, eggplant, potato | N/A | N/A |
What Are the Best Tips for Success?
- Drainage is everything. Mold is the top enemy — always prop your jar at an angle so water drains completely
- Rinse twice daily. Morning and evening rinses keep things fresh without waterlogging
- Sterilize jars before starting a new batch — hot soapy water or the dishwasher works perfectly
- Start multiple jars a few days apart so you always have a fresh batch coming along
- Store harvested microgreens in a container lined with paper towel in the fridge for 3 to 5 days
How Can You Use Your Microgreens?
Microgreens are incredibly versatile — toss them on salads, soups, sandwiches, avocado toast, scrambled eggs, or grain bowls. Blend them into smoothies for a nutrient boost. I add a handful to almost every meal — they make even a simple sourdough toast feel restaurant-worthy. Pair them with a fresh herb garden and you will never run out of ways to garnish your cooking. The Johnny’s Selected Seeds growing library has great variety-specific tips if you want to explore further.
Growing microgreens in mason jars is one of those small acts that makes you feel a little more connected to your food, a little more self-sufficient, and a whole lot more excited about lunch. Give it a try this week — your windowsill is waiting.
Frequently Asked Questions
Are microgreens and sprouts the same thing?
No. Sprouts are germinated in water in the dark and eaten whole (root and all). Microgreens are grown in light, develop true leaves, and are snipped at the stem. Microgreens have more flavor and nutrition.
Can I grow microgreens without soil?
Yes! Mason jar microgreens grow in water alone using the rinse-and-drain method. You can also grow them on damp paper towels or coconut coir mats.
How much do microgreens cost to grow at home?
A tablespoon of organic sprouting seeds costs roughly $0.25–$0.50 and produces a full jar of microgreens — compared to $3–$5 for a small clamshell at the grocery store.
Are microgreens safe to eat?
Yes, when grown from food-safe sprouting seeds and rinsed properly. Avoid nightshade family seeds (tomato, pepper, eggplant, potato) as they produce toxic alkaloids in the sprout stage.
