Seed Science 101

By Melanie Mathieson
The Gardening Guru

Starting plants from seed is a fairly easy task, but a review of Seed Science 101 will help to ensure success and keep your work to a minimum.
It even may offer an answer to why those seeds didn’t germinate a few years ago.
•Seed viability
Do you have some seeds saved from a few years ago? If so, there are a few ways of testing whether they will germinate.
Pour the packet of seeds into a lukewarm glass of water. The seeds that sink to the bottom of the glass have a good chance of germinating while those that float on the surface of the water are dead and should be discarded.
Discard all of the floating seeds, then pour the water thorough a strainer to recover the viable ones.
These seeds can be planted when damp. But if you’re waiting a few days before planting, make sure you dry the seeds thoroughly before storing until needed in order to prevent mould.
Another method of determining seed viability is to scatter about 30 seeds over a damp paper towel, and top with another damp paper towel. Then either place the towels in a tray, keeping them moist, or place in a ziploc plastic bag and seal.
The towels should be moist at all times, but not soaking wet (use a mist spray bottle to keep moist).
After a few days, check to see if the seeds have sprouted. Count the total and determine the percentage of seeds that have sprouted. This will help you to determine how much seed to plant in order to get a good crop.
You can use the seeds that have germinated by planting them directly into potting mix or the garden, if you wish.
This also is a good technique to use if you have a few seeds left in a packet. Start them on the moist paper towels and then transplant when they sprout so you do not lose any of the seed.
Just make sure you use tweezers to handle these small sprouts—and handle with great care when placing in the potting mix or your planting bed.
•Hybrid species
If you have saved seed from a spectacular plant that you had in the garden last year, remember that hybridized seeds, in most cases, will not produce the hybridized plant you collected the seed from.
Hybrid plants are crosses, and the seed that develops from the hybridized plant often has the dominate characteristics from one of the plants used in the cross.
As well, many times the seed produced by a hybrid species is sterile.
To avoid disappointment, make sure you follow the paper towel germination technique to sprout the seeds first and then transplant. These seeds still will produce flowers or vegetables, but they will produce a variation of the original plant.
This can be a fun exercise if you like garden surprises. Just make sure you mark them well in the garden so you know what to expect come harvest time.
•Germinating seeds
Many seeds will germinate faster if the soil they are in is warmed from the bottom.
Until the seedlings have grown upright and have the first signs of leaves, place the tray in a warm spot. The top of the fridge or the water heater is a great place for this (just make sure you do not cut off the air circulation to the back of the fridge or around the fan on the water heater).
Some gardeners place a heating pad in the bottom of wooden tray (set on “low” for a few hours at a time) and then place the tray of seedlings on top. Or, with many homes having radiant floor heating today, the trays can get warmth from below when set right on the floor.
•Stratification
Some seeds need a dormant cold treatment before they will sprout—a process called stratification. Check the instructions on your seed packet as the stratification period can vary from a few weeks to a few months.
For those that are only a few weeks, you still have time to pop them in your freezer until the spring thaw. Place the seed packets inside a plastic bag, seal, and pop in the freezer until planting time (you may want to mark your calendar with a reminder so you don’t forget them).
You also can plant these seeds in a tray with a moist mixture of 50 percent peat moss and 50 percent sand, place it in a plastic bag, seal, and then place in the freezer for the required time.
If you have seeds that require months of stratification, you can store them in the freezer until next spring or save them until fall and sow directly in the soil in mid-October and let Mother Nature do the stratification for you.
Just mark this area well so you don’t mistake these seedlings for weeds early next spring.
Seeds that need stratification include bells of Ireland, bleeding heart, columbine, most evergreen trees, many shrub species, cotoneaster, daylily, euonymous, juniper, hellebore, lavender, lupines, peony, phlox, primula, trillium, and viola (note: only the seeds need cold treatment, not small plants you may purchase).
•Scarification
Some seeds have a very heavy, hard coat that needs to be penetrated before they can germinate. This process is called scarification.
You can scarify large seeds by making a weak or thin spot in the coat, either by nicking it gently with a knife or rubbing a spot with a nail file, emery board, or fine sandpaper.
Where you treat the seed will be where the sprout will break through the coat.
For a less labour-intensive treatment or a great way to treat small seeds, soak the seeds for 24 hours in hot water (190 degrees F) at a 6:1 water-to-seed ratio.
Seeds that benefit from scarification include apples, beets, beans (all varieties), canna lily, carrots, celery, impatiens, lupins, morning glory, sweet peas, pansy, peas, parsley, fruit trees whose seed is a pit, and trees or shrubs whose seed is a nut.
•Deterring bacteria/fungus
Many seedlings fail because of infection from microscopic bacteria or fungus. To minimize seedling failure, treat all seeds with a hot water bath (75 degrees F) for 30 minutes before planting.
You also can buy a commercial fungicide (e.g. captan) that you can apply to seeds before planting. This will help to prevent soil moulds and bacteria, as well as damping off in your seedlings.
Starting plants from seeds for transplanting at a later date, or sowing directly into your garden, is a great way to save money.
Following these tips will help ensure the plants you sow from seed get off to the right start and you only have to do it once, which will keep you on budget and on schedule.

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