More in Outdoors
Although there may be the temptation to cut spent flowers back, allow plants to form their seedpods.
When the seedpods are just about to open and release the seeds or they're brown and dried, remove them from the plants and place pods and all in a paper bag. Make sure to label the bag with the plant name and collection date. Harvest seeds only from healthy plants to rogue out less vigorous selections. Do this on a warm, dry day to prevent mold and allow about three weeks for the pods to dry. Seeds should remain in their natural pod or husk until they're dry, hard and brittle.
Tip: Do your research; some plants propagate better from cuttings or division rather than seed.
Gently shake the paper bag to release the seeds from their seedpods and remove the seeds from the bag. Note: some seedpods may need additional coaxing to open and seeds may require manual removal. Spread the seeds on newspaper or fine mesh screen and allow them to dry for one more week. Or, place seeds inside small glass jars, like recycled baby food jars, and add packets of silica, such as those found inside shoeboxes. Silica gel can also be found at specialty garden centers. The silica draws any moisture inside the jar away from the seeds. Remove the silica gel after one week, and the seeds remain nice and dry. Make sure to keep seeds labeled.
Put collected seeds in plain envelopes; label each one with the plant name and collection date and seal it. Leave commercial seeds in their original packets, taped shut and marked with the year purchased. Small seeds should be stored in a mesh or paper bag. Don't use plastic bags because it encourages mildew. Place the envelopes, packets and bags in a container with an airtight lid, and store them in a cool, dry location, such as a refrigerator. It's best to plant this year's seed in next year’s garden since germination rates vary depending on seed quality and storage conditions.