Chewin’ on Seeds (Assessing Seed Maturity)


Now that fall has arrived, folks are often curious about when to harvest seeds that they’re saving from their garden. Although seed maturity can often be evaluated by simply touching or viewing the fruit or vegetable, SSE’s Farm Manager Bryan Stuart has a more unique approach for some seeds – he chews on them.

While harvesting eggplant for seeds from one of the many Heritage Farm gardens last week, Bryan would frequently pull an eggplant fruit from the plant, tear it open, and pop a handful of the seeds into his mouth. As he chewed on them, he took note of their hardness and listened for any audible ‘crunch’ to indicate that the seeds were mature and the fruits were ready to harvest for seed.

While it isn’t necessary to chew on all of your seeds to assess their maturity, Bryan’s technique demonstrates a certain quality of mature seeds – they are often very hard. Below are a few notes regarding seed maturity for several common, annual plant types:

Beans & Peas: Pods should be brown, dry and brittle before harvest, and the seeds inside should be hard as rocks. If it is a particularly wet fall or you’re expecting an early frost, you may pull up entire plants and move them to a garage or basement to finish maturing and drying.

Corn: Husks should be brown, dry and brittle, the silks should be dark and dry, and the kernels should be extremely hard.


Eggplant, ripe for seed saving

Cucumbers: Fruits must be left on the vine until they begin to turn yellow and their skin becomes tough. Seeds inside should be plump and firm.

Eggplant: Fruits should be left on the plant until they begin to turn yellow and their skin becomes tough. Seeds inside should be plump and hard (or crunchy if you’re chewing on them).

Lettuce: Two to three weeks after the lettuce flowers have opened, the seeds should be mature. Look for feathery parachute-like structures (think dandelions) before harvesting.

Melons and Watermelons: Harvest fruits as you would for eating and simply reserve some of the seeds or leave the fruits on the vine until they soften slightly (this may improve seed quality, but you won’t want to eat the melons at this point). Seeds inside should be plump and firm.

Okra: Pods should be brown and dry, and they will begin to split open when seeds are ready for harvest. The seeds should be very hard.

Okra pod, splitting

Okra pod, splitting

Peppers: Seeds are ready when the pepper fruit has matured to its final color.

Radishes: Pods should be brown, dry and brittle before harvest, and the seeds inside should be extremely hard.

Squash: Fruits should be left to mature on the vine until the skin has become extremely hard. Harvest fruits before first frost and store up to two months in cool conditions (50-60 degrees) to allow the seeds to mature further. Seeds should be plump and firm.

Tomatoes: Seeds are ready when the tomato is ready to be eaten.

Remember to allow your seeds to dry completely before storage, because any moisture in and around the seeds will cause problems with germination. Then when you are ready to store your seeds, check out this blog for some seed storage tips!

Find more seed saving resources here.


Seed Savers Exchange is a non-profit organization dedicated to conserving and promoting America’s culturally diverse but endangered garden and food crop heritage for future generations by collecting, growing, and sharing heirloom seeds and plants.

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  1. Color mentions are a bit misleading, especially for eggplant and cucumbers. We happen to have WHITE eggplant and YELLOW cucumbers. I know there are several other colors available for them as well.

    Would love to know more about the brassicas as well.

    • All eggplant fruits, even white ones, will ripen to yellow (or at the very least produce yellow stripes) if they’re left on the plant long enough – if you harvest them white or green or pink or purple, the seeds are most likely immature yet. Cukes come in all colors too, but they’ll also ripen to yellow when the seeds are mature.

  2. gammy/tammy says:

    great info. thanks!