How Long Do Microgreen Seeds Last? Storing Seeds in Indian Heat and Humidity

✍️ Sonia Pardasani, Founder BageechaBox | 🕐 4 min read | 🌱 Seed Guide

Quick answer: Stored well — airtight, cool, dry and dark — most microgreen seeds keep good germination for a year or more, and small brassica seeds like radish and mustard often much longer. Stored badly in an open packet through an Indian monsoon, the same seeds can lose much of their germination within months. Moisture and heat are the two things to control.

Seeds look like they're asleep, but they are living things, slowly using up their stored energy. Every bit of heat and moisture speeds that up. In Delhi, where a packet can go from 45°C summer to 90% monsoon humidity in a few weeks, storage matters more than almost anywhere else.

Which Seeds Last Longest?

A general guide, assuming good airtight storage:

Keeps well longest	Keeps well	Use sooner
Radish, mustard, broccoli, cabbage, kale, pak choi, turnip	Methi, peas, moong, wheatgrass, beetroot, spinach, amaranth	Sunflower and other oily seeds, any seed opened during monsoon

Oil-rich seeds like sunflower age faster because their oils slowly go rancid. For best microgreen results, I recommend using any opened packet within about a year — and testing it first if it has been longer.

The Jar-and-Silica Method

Step 1 — Use an airtight jar

A glass jar with a rubber seal or a tight steel dabba works far better than a folded packet. Keep each variety in its own labelled pouch inside the jar, with the date you opened it.

Step 2 — Add a moisture absorber

Drop in a sachet of silica gel — the kind that comes in shoe boxes and medicine bottles is fine. If you don't have one, a small cloth pouch of dry, uncooked rice helps too.

Step 3 — Choose the coolest dark spot

An inside cupboard away from the kitchen stove and sunny walls is ideal. Never store seeds on top of the fridge, where warm air collects.

Step 4 — The fridge option

A sealed jar in the fridge keeps seeds even longer. The one rule: let the jar come to room temperature before opening it, otherwise moisture condenses on the cold seeds.

Monsoon Warning Signs

• Clumping seeds — they have absorbed moisture
• Musty smell — mould has started; discard
• White fuzz or dark spots — discard; don't sow mouldy seed
• Tiny insects or holes — discard and clean the jar

Not Sure If Your Seeds Are Still Good?

Don't sow a whole tray to find out. A 5-day paper towel test with 20 seeds tells you the germination rate and how thickly to sow.

Frequently Asked Questions

Q: How long do microgreen seeds last?

Stored airtight in a cool, dry, dark place, most keep good germination for a year or more; small brassica seeds often longer. Poor storage in humid weather can ruin them within months.

Q: Can I store microgreen seeds in the fridge?

Yes, in a sealed jar. Let the jar reach room temperature before opening so moisture doesn't condense on the seeds.

Q: Are old seeds safe to use?

If they are clean, dry and free of mould or insects, yes — they may just germinate less. Test them first. Discard any seed that smells musty or shows fuzz.

Q: Why did my seeds stop germinating after the monsoon?

Humidity. Seeds in an open or loosely folded packet absorb moisture from the air, which uses up their stored energy. Keep them airtight with silica gel from June to September.