by Carl White
MUN Botanical Garden

Collecting seed is a good and inexpensive way to increase the numbers of your favourite plants. Seed can be traded with friends, and most gardeners will save you a few if you show interest.

Collection   Timing is very important when collecting seed. Gathering unripe seed is a waste of time, and overripe seeds will have already dispersed, leaving you with an empty capsule. Select the plants early and watch the development closely. It's a good idea to mark the plants so nobody cuts them down. A couple of warm days can make a big difference to seed maturity; once they start to disperse they can go very quickly. Your collection kit should contain: paper bags about 3" x 5"(not plastic), small shears, a pencil, and stapler or tape to close the bags. This combined with a small bucket will give you a unit that you won't mind taking with you on every visit to your garden, which you should do daily once the seed starts to ripen.

Many garden plants bear their seed in capsules or pods (poppies, irises, bellflowers). Watch the pods and when they start to split remove them. You can often hear the seed rattling around inside, which is a good indication of ripeness. Take one pod and open it into your hand. Seeds should be brown to black in colour and move freely around in your hand (not sticky). If ripe, cut off pods and place them into the collection bag and label with plant name and date. It is often better to wait until the seed is dispersing and get what is left than it is to collect early and get all unripe seed that will not germinate. Some seedheads are fluffy and chaffy (asters, clematis, calendulas), and you may have trouble distinguishing seeds from chaff. Collect the whole seedhead and if you can't separate the seeds during cleaning, store and sow the whole works. With small fruits and berries, if the berry is ripe the seed is usually ripe.

Cleaning   Seeds should be dry and reasonably free of debris before storage. To separate seed from debris, pour contents of collection bag onto a cookie sheet or large tray. Do one bag at a time. Move the pile to one end of the tray and elevate that end to about a 30 degree angle. Tap the bottom of the tray with your finger. The seeds will roll faster than the debris and will collect at the bottom of the tray. Remove separated seed and repeat until clean.

Seeds from small fruits (cherry, dogberry, elderberry, etc.) should be removed from the fruit. Do one lot at a time. Berries may look very different but their seeds look much alike. To clean, place berries on a tray and flatten with a block of 2" x 4". Then put the whole mess into a large bowl or bucket, add water and stir. The heavier, filled seed will sink to the bottom and the skins and bits of fruit will float to the top. Skim off the debris and repeat. Lay seeds on paper towel and pat dry until seeds roll freely.

Storage   Seeds of some species store well, while others will remain viable for only a year or two. I have grown trees from seed that was 30 years old and have had poor germination from seed that was only a few years old. The best results come from seed that is one or two years old.

When the seed has been cleaned and is dry to the touch it is ready to store. For containers you can use little paper envelopes, small paper bags or pill bottles. I find the 35mm film container about the best. They are strong, have good capacity, seal well, are easily available and labelling tape sticks well to them. It is very important to label your seed containers with the plant name and collection date. Anyone who has done any amount of seed collections has put away unlabelled seed, saying " I know what that is." More often than not this turns into "What is this?" a few months down the road. Containers should then be placed in the fridge (not freezer). The best temperature for seed storage is between three and five degrees C. Most people keep their refrigerators around this range.