1. What is a seed?

seed = seed coat + embryo (, an immature plant with all the parts of the adult plant ) + endosperm (food that will nourish the embryo during its early stages of development ) + (dissemination mechanism)

2. Seed viability.

10 = 100% or perfect germination
9 = 90% or excellent
8 = 80% or good
6-7 = 60-70% or poor -- sow more thickly
5 or less = 50% or less -- throw the seed out!

2 a) Seed which can be dried.

Most seed can survive 6 - 12 months of dry storage at room temperature, others much longer. Just keep it out of direct sunlight or out of humid areas. There is no need to store most seed in the refrigerator. [I recently germinated 3 year old Sun Rose (Helianthemum mutabile) and poppies with 100% germination]

2 b) Seed which needs to be planted fresh. (Seed from native woodlands generally do best germinated fresh.)

Some suppliers ship dead seed of these varieties because they ship it dried! Seed of some species are known to be totally killed by dry storage at either 20^oC or 5^oC.

- Bleeding Heart (Dicentra specactabilis)
- Blood Root (Sanguinaria canadensis)
- Celandine (Chelidonium majeus)
- Foam Flower (Tiarella cordifolia) [I have a few germinating at 70⁰C. after 3 weeks]
- Gas Plant (Dictamnus)
- Monk's Hood (Aconitum)
- Pasque Flower (Anenome pulsatilla)
- Virginia Bluebell (Mertensia virginialis)
- Trillium (Trillium grandiflorum)

It is easy to plant seed of the above varieties in the gardens, at the base of parent plants, or to create special germination beds.

In many temperate-zone seeds, fresh seed is prevented from germinating before the spring of the following year by blocking chemicals. Drying destroys the delay mechanism. The length of time for the drying is dependent upon the species, the temperature, and the relative humidity. These seeds usually prefer to be germinated at 20^o C.

- The amount of dry storage time ranges from as short as 3 weeks (barley) to 5 years (Rumex crispus- a variety of dock)

- Most annuals, grasses, campanulas, asters and garden vegetables are examples.

- If seeds in this category are left on the plant to be exposed to moisture (rain & dew), they lose their viability before they can germinate in favourable spring conditions. Therefore, seed collection of many of our locally grown perennials should occur as soon as the seed is ripe.

Destruction of inhibiting system in presence of moisture either at:

i) 20^o C. (70^o F) or
ii) at 5^o C. (40^o F.) = Cold Stratification

In many species, the germination inhibitors are destroyed simply by exposure to moisture. There is a delay before germination occurs but then there is a uniform germination of the seed. Most seeds are of this type.

In some varieties, 5^o C. moist storage is required (from days to months) to allow the inhibitor to be destroyed.

Germination then takes place at either 5^o C. or 20^o C. depending on the varieties. If working with 5^o C. varieties, make sure that they are taken out of the fridge once germination occurs to allow light for the photosynthetic processes to get going or the seedlings will die.

Seeds embedded in fruits.

Usually the pulp contains powerful inhibitors and need water to flush out the inhibitor to permit germination. Germination begins several days after the flushing process. In some species the flushing need ony be for 10 minutes. In others, flushing must last for days or weeks.

In nature, digestion in birds or animals effects this process. Also in some fruits, germination can take place within the fruit as time proceeds. The inhibitors appear to lose their potency or are leached away from the seed.

Seeds with impermeable seed coats have the longest dry storage capabilities.

Water needs to get into the seed to begin the germination processes.

- drill hole, file nick etc.
- there are natural fissures in most seed coats.
- for practical purposes, most seeds used by the average gardener don't need to be physically attacked to get germination initiated within a week or two.

Some seeds need a regime of alternating cold-warm exposures to destroy the inhibitors.

For the following, it is best to place the seed in pots and place them outside to be exposed to the natural temperatures of winter and spring.

Aquilegia canadensis, Phlox paniculata, and Sanguinaria canadensis.

Light is a requirement for destroying inhibitors in some plant varieties.

Seeds from plants naturally growing in swamps and forests generally require exposure to light to destroy the inhibitors.

In swamps and woodlands, light is more apt to be a limiting factor than moisture so the requirement for light for germination has survival value.

When catalogues say surface sow, it can be inferred that light is required. Place the seed in plastic baggies under fluorescent lights, never in direct sunlight or under incandescent bulbs, set for 12 hours light and 12 hours dark.

- e.g. Cardinal Flower (Lobelia cardinalis), Red Husker Penstemon (Penstemon digitalis 'Red Husker')

Milk weed varieties demonstrate an interesting example of the light requirements based on the natural habits in which they grow.

- Butterfly Weed (Asclepias tuberosa), a dry land variety, does not need light for germination.

- Swamp Milkweed (Asclepias incarnata), a swamp variety, requires light.

- Common Milkweed) Asclepias syriacus, which grows in intermediate environments, benefits from light but germination is not dependent upon it.

In some species, both prolonged cold treatment and light are required to destroy inhibitors. 3 months at 5^oC. is require for Asclepias incarnata and Verbena hastata.

It's best to not use ordinary garden soil for indoor germination.

- It contains too many soil-borne pathogens for successful germination.
- It is too heavy and tends to crust and pack.

Use fresh soilless mix to avoid fungal and insect (fungus gnats) problems.

1. The key is aeration so that root hairs have oxygen for their metabolic processes.

It's easiest to purchase commercial soiless mix. (General purpose ProMix, Sunshine mix etc. Avoid fine-textured germinating mixes which become water-logged, compacted and favour disease conditions.)

- make sure it contains NO added nutrients.
- for years I have used regular soil-less mix with no added nutrients

A home germinating mix can be made using: 1 part peat moss/ 1 part leaf mold/ 1 part Perlite (Turface or Granite)

Alpine plant's seed can be set on 100% turface with the pot set in water to wick moisture upwards.

2. Sterilization before use:

When using soil-less mixes, the main requirement is to kill fungus gnat eggs which will hatch and, at the larval stage, feast on young root hairs. While manufactures claim their mixes are pest-free, I have lots of trouble with fungus gnats which appear with the introduction of these mixes into the greenhouse.

If using garden soil in the mix, the aim is to kill fungi, weed seeds and insect eggs that can affect the developing seedling.

This is especially important for the following varieties (with thin, soft stems):
Alliums Globeflowers Poppies
Columbines Goat's Beard
Foxgloves Lady's Mantle

Procedures for mixes containing garden soil:

a) pouring boiling water over it, three times.

Place a porous filter paper or other form of fine screening over the soil to keep lighter materials in the mixture from floating up to the surface.

b) microwaving moist mixes.

Moisten the mix, but not to the point of being squishy.

- Place the soil in a plastic bag (polypropylene cooking bags are best) and loosely twist close the bag : alternatively use a microwave-able bowl with a loosely fitting cover.
- Heat the soil, at high power, at the rate of 2 1/2 minutes for 2 cups of soil or 7 1/2 minutes for 8 cups of soil.
- If damping-off problems are anticipated, double the heating time.
- After microwaving soil, thoroughly clean the oven and especially the door seal.

c) oven sterilization

Place moistened soil mix in covered (aluminum foil) shallow trays or baking pans in 250 degrees F oven for 45 minutes (the length of time necessary for sterilization depends on the volume of soil, as well as its moisture content. Dry soil cannot be sterilized well). The aim is to get the soil heated to 160 to 180 degrees F.

- For soilless germination mix, use 8 cups of moderately moist mix and heat, at high power, for 10 minutes.

Direct seeding in Garden:

- Seeds with bigger amounts of endosperm can feed the embryo plant longer, while it works its way toward light. Therefore, big seeds can usually be planted deeper.

- Seeds must absorb water to get germination going. Therefore, presoaking seeds may speed up the process.

-Available water is important to the newly emerged root. Therefore, you should plant seeds a little deeper in the middle of summer, when the top of the soil dries out quickly.

Pre-germination indoors

1. Sow the properly conditioned (e.g. cold treatment if required) seed either on the soil surface or slightly covered as per instructions (e.g. T&M booklet) This can be done using either small germination cubes or regular plant pots. Seed can be mass planted in one pot and then pricked out and potted up as they mature. Alternatively, seed can be individually placed in larger pots to minimize transplanting work

- Start seeds four to eight weeks before the plant-out date in a particular area (average last killing frost date). Starting too early usually results in spindly plants due to lack of sufficient light and crowding.

2. Place pots in plastic baggies & seal, or in dome-covered germination trays.

3. Place pots in appropriate light. Most seed germinates quite readily at room temperature when exposed to light (but not direct sunlight). Relatively few require darkness for germination. Refer to T&M booklet (or table downloaded from internet as referenced above) for those requiring darkness. As soon as germination is noted, move the seedlings to proper lighting.

4. When seeds germinate, move them gradually (over two or three days) into brighter light.

Alternative Germinating Technique. (This is the method I use for nearly all purchased seed)

Germinate in small plastic drinking cups on moistened coffee filters. Glasses (labelled of course) can be stacked and placed in sealed plastic bags to maintain high humidity levels. This method allows many varieties to be started in a small space. If refrigeration is required, minimal space is occupied.

After germination, prick out as individual seed germinates and plant in sterilized mix as above. Don't let the primary roots develop too many small white root hairs before doing the pricking out. These small white roots quickly penetrate the coffee filter paper and make it very difficult to do the moving without damaging the very tender roots. I check each cup of seeds each day to move those ready for relocation into soil.

Transplanting and Growing On Seedlings.

1. When seedlings have produced their first pair of true leaves (the leaves above the cotyledons or "seed leaves"), it is time to transplant them into larger pots. We use 3 to 3.5 inch pots (at the rim) for most perennials – 2" for slower growing alpines. The pots are about 3 inches deep to provide generous amounts of growing medium and moisture-holding capabilities.

2. Prepare the receiving pots by filling with pre-moistened soil and make a planting hole large enough to accommodate the root without breaking off the growing tip.

3. Place the seedlings in their new pots.

4. Water in the seedling with ordinary water and let the seedling establish itself for about 3 days before adding fertilizer solution.

Before 2005 we used the following fertilization technique (please read Since 2005 below):

The first fertilization was done with a transplanting fertilizer solution (at 1/2 recommended strength). We used 1 tablespoon 10:52:10 per 4 litres of water. This fertilizer promotes root formation. We used this formulation for the first 3 weeks for most seedlings. Subsequent fertilization (begining in the 4th week) was done with 15:30:15 to give all-round good growth. We fertilized weekly by preparing a solution 1/4 the recommended strength on the label. If a daily fertilizing regime is chosen, prepare and use a 1/10 strength solution. Add enough solution to have water draining from the pots. This prevents salt build-up, which is harmful to roots, in the soil. Which is best? For the home gardener, the weekly schedule is appropriate.

New Info - Since 2005 we are using the following fertilization technique:

I suggest reading my article 'Plants Crave Fungi: The benefits of adding fungi to soil at planting time' before going any further. Click here for this article. It will set the scene for why I have changed my procedures.

Actually, the choice of fertilizer is the only modification to my fertilization regime. With the recent adoption of using potting soils containing mycorrhyzal fungi, it is now required that translanting fertilizers containing high phosphorus fertilizers not be used. High concentrations of phosphorus significantly inhibit the growth of the beneficial fungi which colonize the developing root hairs and confer the improved root development characteristics stimulated by the fungi preent in the potting soil.

I now use a balanced fertilizer formulation in which the labelled phosphorus percentage is no more than twice the nitrogen percentage: water-soluble fertilizer formulations of 7:7:7 and 15:30:15 are acceptable; 10:52:10 is not acceptable.

We have almost totally changed our fertilization practices to using fish emulsion as our fertilizer of choice. We (and our customers) are benefiting from better overall plant health from seedling stage to saleble plants. We fertilize weekly, with half-strength label recommendations, after a three day settling-in period in which tap water is used to keep soils moist. We add enough solution to have water draining from the pots.

5. Place pots under fluorescent lights or on window ledges.

If using window ledges, make sure the seedlings do not get too cold.

If using fluorescent lights, place the lights about 2" above the leaves and keep raising them as required, maintaining the 2" height throughout their growth period.

Aim for 16 hours of light at room temperature for good plant development.

Plants that have been growing indoors can't be planted abruptly into the garden without injury. To prevent any damage, they should be "hardened" before planting outdoors. This process should be started at least two weeks before planting in the garden.

If possible, plants should be moved to cooler temperatures outdoors in a shady location. A cold frame is excellent for this purpose. When first put outdoors, keep in the shade, but gradually move plants into sunlight for short periods each day.

Gradually increase the length of exposure. Don't put tender seedlings outdoors on windy days or when temperatures are below 45 degrees F. Reduce the frequency of watering to slow growth but don't allow plants to wilt. Even cold-hardy plants such as cabbage and pansy will be hurt if exposed to freezing temperatures before they have been hardened. After proper hardening, however, cold hardy plants can be planted outdoors, and light frosts will not damage them. Plants which are not frost-hardy will have to be covered if below freezing temperatures are forecast even if they are ‘hardened’.

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