How to germinate seeds

This information was produced when we realised many growers in the Netherlands are quite advanced when it comes to growing, but have no idea how to germinate and cultivate a seedling successfully. That's inevitable in a 'clone culture' such as ours. However, the arrival of feminine seeds urges the availability of more information on this subject. Experience is more useful than anything in this matter. Here you'll find some advice and possibilities to allow your seedlings to become robust and healthy growing/flowering plants.

Growing Media: Rockwool plugs, Rockwool blocks, Pots with soil, Jiffy Pots, Outdoor

Rockwool plugs
A fine medium for germinating. The biggest problem is that you'll have to move the plug to a block or soil in a matter of two to three days. After all, you'd like to give the penroot an optimum chance of developing fully. In other words: it's preferable to directly sow into the bloc to prevent unnecessary work.

Rockwool blocks
Especially a fine medium for large-scale growers. Flush your blocks very well (with pH 5.3) to lower the pH value of the medium and put the blocks on top of each other; rockwool on rockwool. You'll notice the water is drawn away from the top-blocks, so you don't have to deal with a saturated block for at least a week. Regulating humidity is crucial. Now put 110 blocks (of 7.5 by 7.5 cm) in a so called Duma tray, or 220 on a 'Danish tray', and fill the holes in the blocks with sowing/germinating soil (read General Notes). After sowing, about 0.5 to 1 cm deep, cover everything for about two days with plastic to prevent from drying and keep the tray in a warm space. Make sure the tray gets lit after those two days, for at a temperature of 23°C the seeds will germinate within two days. Experience has shown that by doing so the plants don't lose a minute of their growing potential when you put the blocks on the slabs after 12-14 days.

Pots with soil
The most beautiful, the best, the most natural and easiest medium. Use well pre-fertilized potting soil, fill the pots to about three quarters of their volume with this soil, fill up the remaining quarter with sowing/germinating soil. Press the combined content of the pot to an even surface to prevent the water from flushing away the seeds while watering (use a small watering-can or sprayer). Plant the seeds 0.5 to 1 cm deep. Preferably use disposable plastic pots, from which you cut out the bottom later on to allow for a smooth transient to the slab or bigger pot later on. These pots can be placed directly on top of the slab. Make sure you fix the drippers at the back of the slab and not in the pot. The reason for this is that the plant releases it's waste (salts and minerals) in the top layer of the medium, and it's not a good idea to flush this waste to the drinking roots every time you water. Another benefit is that you can place considerably more (female) seedlings on a square meter than you could with clones.

Jiffy pots
A more expensive method which has both advantages and disadvantages; the pots dry out very rapidly, and are only suitable for soil cultivation. When they get too humid, molds develop quickly. A fine medium, but you have to observe them carefully and move the seedlings to their real medium as soon as possible. The biological approach will appeal to many, but on a larger scale you'll most likely encounter difficulties.

The most natural way, but very much depending on the wheather. Especially in countries with a sea climate, such as Holland or England, plants come through their vegetative stage pretty nicely, but get lost because of too much humidity in autumn. Don't take any risk with sowing, and sow only when you can be sure there will be no more frost. Only when temperatures increase, the plants will develop real growing speed. Don't sow any deeper than 1 cm on a soil that is as 'airy' as possible. When it doesn't rain make sure the soil keeps somewhat humid in the following days. Note that the seeds don't like to swim! Extra nutrition should not be necessary during the cycle, but if you don't use fertilized soil give the plants some water to which you have added some fertilizer every two weeks. Make sure you don't water directly along the stem to prevent unnecessary salts and minerals to reach the drinking roots. Growing indoors at first is an option, and gives you the opportunity to control the number of light-hours. If you keep the plants under 20 hours for a long time, and putting them outside when the daylight is already decreasing, you gain time and your plants will reach the flowering stage sooner. Make sure the plants don't stagnate and keep going, for that of course is essential in this case.

General Notes
Make sure you choose a sowing/germinating soil which contains a lot of fine sand. Masonry sand or sand for playgrounds as an addition is just fine. Too many fibres cause problems with germinating. If you want to be absolutely sure and create an optimum chance for each seed, sieve the soil mixture before use! The helmet (seed cover) and the film which envelopes the seed should remain in the medium when the seeds germinates. Too light a soil will hamper this process. Keep your water to pH 6.3, and keep the seedlings humid, but not TOO wet. A fine water sprayer works miracles here. Make sure the seedlings receive FULL light when they germinate and leave it like that for at least 20 hours the first couple of days. Make sure your tube lights hang as close to the seedlings as possible (a couple of centimeters)! A 400 watt lamp can be hung as low as 45 cm and a 600 watt lamp as low as 55 cm.

Don't be afraid, the seedlings can very well handle this, even though a good movement of air underneath the lamp is very important (ventilator!).

Make sure you spray in time, until the hull, that may come up when the seed germinates, has dropped off, as well as the protective film which envelopes the seed. This is necessary to prevent the hull and protective film to dry out, which sometimes result in sticking to the germinating seedling, which as a consequence, is hampered in it's development. Stop spraying water when all seedlings are overground, too allow for your seedlings to work at maximum efficiency underground. Offering too much humidity to the leaf often results in a less developed rootsystem. Contrary to clones, seedlings have a reasonable resistance to dry air. When using germinating trays, things often go wrong because of excessive heat and humidity.

Because we germinate and grow our seeds indoors on a warm medium, the plants tend to shoot up rather thinly, which causes weak and excessively high plants. This can only be prevented by hanging the lights as low as possible.

Lowering soil temperature could be an option, if it weren't for the growing speed we don't want to lose.

The biggest mistake being made is: not bringing the light close enough to the developing seedling!

Remember that the first two to three hours partly determine the rest of the plant's life!

Start giving some nutrition only after the plants have been in the light for two days. Start with a very light nutrition and keep the water to pH 6.3. Note: the ballast caused by a measurable EC in your tapwater can NOT be seen as nutrition. If you don't have a pH measuring device at hand, try to work with rainwater or add a drop of natural vinegar to the water - and be aware that your first purchase 'should' be a pH meter. Preferably use 'pure' nutrition that could also be used as leaf-nutrition. Doing so minimizes your chances of failure.