Growing plants from seed

In a regular nursery the growers often keep the plant through at least one season so that you get instant gratification with plants. In fact, they prefer to sell the plants as they are coming into flower because they know you are more likely to buy a plant that is in the process of flowering. You pay more for this level of service. With native plant operations, the plants are often sold in the first season of growth and you may still have to wait a year or two or more for flowering to occur.

Gardeners grow plants from seeds for the following reasons:

a) They have a large plot and need lots of individual plants to fill in the space. It is cheaper to start from seed.

b) They are unable to buy the plant locally, but can easily obtain the seeds online.

c) It is fun to grow plants from seed.

 

You have a few choices for seed treatment:

i) You can simply sew the seed on the ground. In this case, I would use a lot more seed than you need and would rake the surface lightly before patting the seed down to improve contact between the seed and the soil.

ii) You can plant the seeds in pots or trays in December and leave the pots outside all winter. You may need to protect your pots from meddling animals by using mesh or some other protection. The freeze thaw cycles will cause the seed to germinate in the spring when the temperature rises.

iii) You can replicate the freeze/thaw cycle by placing your seed packet in a plastic sandwich bag. Each day, move the bag from the freezer to the fridge and then back to the freezer on the following day. Do this for at least 8 consecutive days in mid-spring. Some people prefer to place the seeds in some soil-less mix with some moisture in a plastic sandwich bag and after treatment, these seeds may start to germinate in the bag.

iv) Some seeds require extra treatments to increase germination rates. These include a light rubbing with sand paper or a quick exposure to boiling water or cutting a tiny opening in the seed coat. If the seed is very small, it probably will need to be sown on the surface of the soil to guarantee exposure to light.

 

Here is what you need for planting seeds in pots:

Small plastic pots or trays which can be bought. Commercial nurseries often will take old pots back so you might be able to get a free supply of these. Clean any recycled pots with mild solution of bleach (1 part bleach to 10 parts water). To obtain the maximum amount of seedlings, use trays. If you are leaving your trays outside, you need to drill holes into the bottom of the sides to allow drainage. A 3/16 drill bit is about right. Seedlings in trays can be carefully transplated in to 4 inch pots to grow through the first season.

Soilless starter mix, which is a blend of vermiculite, perlite, peat moss and perhaps sand. The sphagnum peat moss is good at retaining water. Perlite is a porous rock that retains air and increases the macropores. Vermiculite is better than perlite at retaining water but not as good for providing drainage. Starter mixes often do not have much fertiliser in them so you may need to add fertiliser when your plants get going. If you use potting soil with actual soil in them, you may run into a damping off problem (see below). By using a soilless mix, you avoid the problem of having unwanted plant pathogens and pest while providing a well drained medium with plenty of aeration for your seedlings. It is worth noting that sphagnum moss has to be mined from bogs which is an unsustainable practice that has resulted in destruction of much lowland bog habitat. You might want to consider starter mixes with an alternative ingredient if they are available.

	These pots are 4 inches wide which is the standard size to use for most plants to grow through the season. They are filled with a soil less mixture.

 

Seedlings are prone to attack from various fungi that either damage the roots or which may cause a visible mould to start growing at the base of the plant. Once the damage is done, it is almost impossible to correct. If you want to avoid this problem, you should grow your seeds outside. Inside your house, the humidity is higher, which promotes fungal growth and the fungal spores that cause damping off are more likely to be in the air supply. Often gardeners want to start their seeds early so planting indoors is the only option. Leave space between the plants for air to circulate and plant them somewhere in the house where air circulation is higher. Never pour water onto the plants. Dip the pots in water until you can feel that they are heavier. Under no circumstances, should you cover your native plant seedlings with a plastic lid because this will allow the humidity to build up to levels that favour damping off.

	These starter trays have small amounts of soil in them. They are not designed to keep seedlings in for the whole season as the roots will be too confined to allow the maximum amount of growth to take place. This tray has milkweed seeds which have been pushed firmly onto the soil surface to ensure good contact.

 

You have a few choices for starting in soilless mix. Growers needing large numbers on individual plants should plant the seeds in one large tray. When the seedlings appear, the larger and healthier specimens can be carefully disentangled from surrounding seedlings and planted in their own pot. If you just want a few specimens, then put 3 or 4 seeds in each pot and when the seedlings appear, pull out the ones you don't want. If you are going to plant the seedlings fairly early, then they do not need too much space for root growth. You can use the trays that contain spaces for small amounts of soil. If you are planning on culturing your seedlings all summer, which is my preference, then you need a 4 inch pot to allow for healthy root growth during the first season.

	It is tempting to leave every specimen to grow but because they are so close together, these seedlings will compete with each other for nutrients and their roots will become entangled. Seedlings this close together should be replanted separately or you can just pull the weakest specimens out.

 

 

 

Scientific Name by genus	Common name
Achillea	No pretreatment required.
Actaea	Two seasons of cold and moisture. Remove all the flesh from the fruit as it inhibits germination.
Aesculus parviflora	One season of cold and moisture
Aesculus glabra
Agastache	Surface sow after one season of winter.
Allium	Usually one season of cold and moisture. A. tricoccum needs 2 winters.
Andropogon	No pretreatment required.
Anemone patens	Full season of cold and moisture.
Antennaria	One season of cold and moisture
Aquilegia	It will readily self-sow. It probably does not need any pre-treatment.
Aronia sp.	One season of cold and moisture.
Asarum canadense	Plant the seeds as early as possible in the summer and wait through one full season of cold moisture for germination.
Asclepias	A short season of cold and moisture. Sow these seeds on the soil surface
Aster	One season of cold and moisture.
Astragalus	Sow in the fall and expose seeds to a whole winter or scarify the seeds in spring.
Blephilia	One season of cold and winter. Sow on the surface.
Bouteloua	No pretreatment required.
Bromus kalmii	No pretreatment required.
Campsis	No pretreatment required
Carex	One season of cold and moisture.
Ceanothus americanus	One season of cold and moisture.
Cephalanthus occidentalis	No pretreatment required.
Cercis canadensis	One season of cold and moisture.
Cimicifuga racemosa	Up to 2 seasons of cold and moisture.
Cirsium discolor	As a biennial, it may not need much exposure, but for best results, apply one season of cold and moisture.
Clethra alnifolia	No pretreatment necessary.
Cornus sp.	One season of cold and moisture after removing all the flesh.
Coreopsis	One season of cold and moisture.
Dalea purpurea	No pretreatment necessary.
Delphinium	One season of cold and moisture.
Doellingeria umbellata	One season of cold and moisture.
Echinacea	One season of cold and moisture.
Erigeron	One season of cold and moisture.
Eryngium	One season of cold and moisture.
Eupatorium	One season of cold and moisture.
Euphorbia corollata	Short season of cold and moisture.
Eutrochium	One season of cold and moisture.
Fragaria	One season of cold and moisture.
Gaillardia	No pretreatment required.
Gentiana andrewsii	One season of cold and moisture.
Geum	One season of cold and moisture.
Geranium	One season of cold and moisture.
Heuchera	One season of cold and moisture. Sow these seeds on the soil surface.
Helenium autumnale	No pretreatment required. Sow the small seeds on the surface.
Helianthus	One season of cold and moisture.
Heliopsis	Sow the seed in early spring.
Hepatica	Exposure to two winter treatments
Hibiscus moscheutos	One season of cold and moisture.
Hydrophyllum sp.	One season of cold and moisture.
Hymenoxys herbacea	One season of cold and moisture.
Iris	One season of cold and moisture.
Ipomopsis rubra	One season of cold and moisture.
Koeleria macrantha	One season of cold and moisture.
	One season of cold and moisture.
Liatris	One season of cold and moisture
Lilium	May need two seasons of cold and moisture. L. philadelphicum only needs one season. Be patient with the seedlings and you may need to wait a full year before transplanting them.
Lobelia	One season of cold and moisture (although some seeds will germinate without this). Sow on the surface as exposure to direct sunlight is necessary for germination.
Lonicera	Clean the seeds of all flesh from the berry and expose to cold moisture for 3 months.
Lupinus perennis	One season of cold and moisture.
Mertensia virginica	It self sows quite well. You could collect the seedlings. Otherwise, collect mature seeds and expose to one cold treatment.
Monarda	No pre-treatment is required. Sow on the surface as exposure to light is necessary for germination.
Oenothera	Most species do not require pre-treatment, but exposure to one cold treatment will work for all of them.
Opuntia humifusa	No pretreatment is necessary to get some seeds to germinate.
Panicum virgatum	No pretreatment required.
Parthenocissus	One season of cold and moisture. Remove all traces of fruit flesh from the seeds.
Penstemon	One season of cold and moisture.
Phlox	One season of cold and moisture.
Physostegia	One season of cold and moisture.
Physocarpus	One season of cold and moisture.
Pinus strobus	No pretreatment necessary
Pulsatilla patens	One season of cold and moisture.
Pycnanthemum	Sow on the surface when above zero.
Ratibida	A short season of cold and moisture.
Rosa sp.	2 seasons of cold and moisture.
Rubus sp.	Clean the seeds of all flesh from the berry. The plant requires at least 2 seasons of cold and moisture.
Rudbeckia	R. hirta probably germinates without any treatment. It reseeds prolifcally. All other Rudbeckia require at least a short season of cold and moisture to ensure germination.
Sanguinaria canadensis	Sow the seed in a pot outdoors and leave it for up to two years until germination is observed. Keep the pot somewhere cool and do not let the soil dry out.
Schizachryium scoparium	No pretreatment necessary.
Scrophularia	One season of cold and moisture.
Senna	One season of cold and moisture or scarification.
Silphium	One season of cold and moisture.
Solidago	Most goldenrods need one season of cold and moisture.
Sorghastrum nutans	Like other grasses no pretreatment is required.
Spigelia	One season of cold and moisture.
Spirea	Seeds require one season of cold and moisture. The small seeds should be sown on the surface of the soil.
Sporobolus heterolepis	No pretreatment required.
Tetraneuris herbacea	No pretreatment is required.
Tradescantia sp.	One season of cold and moisture.
Trillium grandiflorum	Two seasons of cold and moisture.
Verbena	One season of cold and moisture. Sow these small seeds on the soil surface.
Vernonia	One season of cold and moisture
Veronicastrum	No pretreatment is necessary.The small seeds should be sown on the surface of the soil.

 

Squirrels love to investigate anything new that is put out in the garden so you should always expect to lose a few pots to them, but take a look at the picture below to see if you can spot something a little bit more unusual.

 

	It is called an American toad.