There are many different methods of seed germination available to the gardener. In this issue we are going to take a quick look at some of the most popular methods of seed germination practised outdoors. Some of the slightly more advanced methods of seed germination are usually common practise in a professional greenhouse setting, whereas here we are mainly interested in what happens when sowing seeds directly into the ground outdoors. Firstly, then let’s take a look at some of the main advantages of growing plants from seed.
Why grow from seed?
Growing plants from seed provides gardeners with a real opportunity to start gardening from scratch. Seed sowing is something that all avid gardeners should try, at least once, before moving onto clones. Growing from seed provides growers with practical knowledge and experience about how seedlings grow and react under different environmental conditions. Seed sowing also teaches gardeners about different cannabis varieties and how best to grow them in the garden. Something worth remembering is that unlike cloneculture no seed is ever the same, no matter how homogeneous the seed line it came from. Each seed is an individual, with its own unique character and its own genetic code. Selecting the right variety of seed for the right garden is then always a starting point. Which seeds to grow?
Seeds are living organisms. There are good batches of seeds and there are bad batches of seeds. It would be nice to suggest that gardeners can go out and purchase the most expensive packet of seeds, from the most expensive seed banks with 100% guaranteed results. In reality, seed stocks vary with a degree of bounce in levels of viability and stability, regardless of the origin, price, and breeder. Like wine, there are good years and there are vintage years. Finding the right seed packet for the right situation is in many ways the gardeners’ privilege today; with so many seed varieties now available the home grower is perhaps spoilt for choice in places.
Generally speaking, seeds from professional breeders come in printed packets. With a clearly marked label that states the cultivated name of the seed variety on it. Some of these names are really well established, while others are still fresh and exciting. Seeds from private breeders on the other hand usually come in an envelope with the name of the strain scribbled onto them in marker pen. Sometimes seeds arrive unlabelled. Either way good seed stock is a good place to start.
Seeds labeled `Outdoor’ often don’t grow well indoors because they grow tall and become unmanageable. Seeds labeled `Indoor’ don’t always perform well outdoors because they die from the first signs of frost and from mold. Tropical varieties may be adapted to suit glasshouse conditions and sometimes very sheltered outdoor positions in the UK, but only where the climate is very mild in Autumn. Temperate varieties are however naturally suited to cooler climates and usually make for the best seeds to be growing outdoors from scratch.
Growing seeds from a particular variety outdoors usually falls down to the experience of the gardener and local weather conditions. Balance this against the consistency of the actual seeds, and the results fall someplace in the middle. Some gardeners grow well with certain breeders, companies, or seeds, outdoors while others don’t. That’s what they call “the Juck of the draw”.
Cultivated Seeds automatic seeds
Cultivated seeds can be sown indoors at any time of year and in any season. One reason for this is that programs of force-flowering and hybridization over successive generations, in heavily `cultivated’ varieties, has ultimately reduced the `survival factor’ in the plants. This phenomena is the same the worldover in any cultivated species of seed plant, not just cannabis. Seed that have been cultivated outdoor (under more natural conditions) however remain slightly more seasonal in character. Outdoor seeds prefer to germinate under a natural photoperiod and cooler temperatures directly outdoors during the Spring months only. Whereas cultivated indoor varieties, are often a lot Kappier to be germinated anytime, with the exception of winter.
Most “Outdoor” cultivar are more tolerant towards cooler climates because of their predominately Afghan ancestry. Plants from the Hindu Kush region, which favor dry soils, warm days, and cold nights, therefore tend to adapt to N. European climates well. Over generations the seed from the Hindu Kush region have learnt to survive under the most extreme conditions. When selected to perform outdoors under European climates these cultigens perform better than their equatorial cousins. The bud density of Afghan / Kush varieties, when grown outdoors in wet European climates, does however expose the plants to the risk of mold.
Other `outdoor cultivar’ may contain South African heritage. Durban Poison plants are grown outdoors in Europe for their early flowering abilities, rather than the ability to withstand the cold (especially during germination time). Plants with mixed Durban / Afghan lineage that have been selected to flower early, to withstand cold temperatures, and to tolerate or even resist conditions of mold, therefore usually make for best plants to be sowing directly outdoors.
When is the best time to sow seeds?
Seeds can be sown indoors all year round. This is because once germination takes place the young seedlings are given an artificial source of light (exceeding 14 hours a day) and a warm temperature (between 8-15 degrees Celsius) to help sustain growth. During the Spring and Summer months seeds can be germinated under more natural conditions outdoors (especcially under glass). This is because daytime temperatures and increased
day-length prompts natural growth in most annual plants. When sowing seeds directly into the ground outdoors the soll temperature MUST be warm enough to sustain growth. Soil temperature varies dramatically depending on local soll type and local micro-climate. Keen gardeners are outside feeling the soil daily, to judge soil temperature accurately in Spring before sowing. Dark soils always warm quicker in Spring and retain some of their warmth into Winter. Whereas sandy / stony soils remain relatively cold throughout the year, partly because they reflect more heat from the sun.
Why is seed dormancy important?
A period of seed dormancy aids seed germination. How many seeds germinate often depends upon the treatment and the age of the seed prior to sowing. A lack of dormancy in seed is usually reflected in low rates of viability when sown. Seed embryos first need time to develop or “overwinter” before they can germinate and grow into seedlings. Cannabis seeds display a combination of physical and chemical dormancy. The seed Shell has a fissure line that slowly lets water in. The seed embryo inside has a natural chemical inhibitor that will prevent germination until the embryo inside is fully developed. A cooler period (over winter) triggers a period of natural hibernation in the fully developed seed embryo. The following season the seed gets warmed by the sun and moistened by the min and germinate into the next generation of plants.
How long can seeds be stored for?
Cannabis seeds hold a shelf life of between 5 to 20 years depending on sub-species. Heavily cultivated seed lines should ideally be sown out soon aller ownership (within a few years) for the best results. This is because domesticated seeds are inherently weak. Landrace seeds may survive for longer periods when stored correctly. In the Jong term, viability rates in both domestic and cultivated seed lins is always reduced with excessive periods of storage.
Preventing Seed Germination
Most varieties of Cannabis seed need a consistent temperature between 15 – 25c to germinate successfully. Certain varieties of seed will however happily germinate at temperatures much lower, between 5 -15c. Different seed then require slightly different environmental conditions to germinate to the best of their ability. All seeds require moisture and a period of raised temperature to germinate. Keeping seed cool, dry, and dark, is the best way to prevent seed germination from happening. Many domestic gardeners use fridges to help mimic the overwintering period in their seed lots (not just cannabis). Old timer gardeners however still prefer to place their seeds into an old biscuit tin (with holes in) over winter.
Which method works best for seeds hydro or soll?
Seed germination is suited to most methods of organic and hydroponic cultivation. The easiest (and most natural way) to sow seeds is to sow them directly into a medium of fresh compost, cover them with a thin layer of soil. Water-in and place them into a warm sunny position. Then wait for the seedlings to hatch. Hydroponically seeds can be germinated in a variety of mediums including, rockwool cubes, plugs, coco fibre, perlite, or vermiculite. Although initial growth is supported by the seedling itself, hydroponic mediums usually require some form of proprietary feed to get seedlings growing. The method that works best is usually down to the individual gardener and his/her situation.
Sowing Seeds Outdoors
The soil bed that seedlings are sown onto outdoors directly relates to plant growth and development. Heavy clay soil sites will burden seed growth as much as light sandy soil sites. It is therefore always important to “prepare” the soil site before seed sowing begins!!!
Firstly the ground should be cleared of any obstruction, such as leafs, twigs and stones. Next a layer of compost or bagged soil can be added to the soil site if required. This is usually the case where gardeners seek either increased drainage in clay soil and/or water holding abilities in sandy soils. Soil sites which are already rich and light may require a few hand fall of coco fiber to get them into shape.
NEVER add fresh manure or fertilizer to a soil site that is about to be sown onto. Any concentration of nitrates in the soil is liable to burn and damage the tender roots of the seedlings as they grow. Manure should therefore be added to soil sites the previous autumn / winter. It is also important not to overwater a soil site too much or it may become to compact to work on.
Next the soil site needs digging or better still forking over evenly until a fine “till” of soil develops across the top of the bed. Seeds can be sown into rows and covered with surrounding soil. Alternatively seeds can blanket scattered across the soil site. Several scatterings may be required to establish an outdoor patch from seed. Spaced sowings, every week from the 1 st of April onwards (in the UK), will strengthen the overall rate of survival in the outdoor seed garden. Likewise seeds can be sown individually into cell trays first, and then planted out into the soil bed a few weeks into the growing season.
Perpetual Seed Gardening
Finding just the right variety of seed, for just the right position in the garden, is the essence of perpetual seed gardening. The quickest and easiest way to establish a perpetual seed garden outdoors is by selecting a seed cultigen that will adapt to the environ quickly, and by sowing out ‘lots’ of seeds. Allow the plants to pollinate themselves that season. Then simply turning the seeded plants back into the soil the season after. Nature will then determine the rate of survival from seeded crop to seeded crop. Over generations, the seed variety will gradually homogenise itself to the garden and the landscape.