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germination guide

Maintaining the ideal temperature (between 22–25°C/71–77°F) and moisture for germination is tricky. Leaving seeds out in the open environment or on a windowsill is far from ideal; a DIY climate-controlled cupboard would do a much better service. A warming mat is perfect for maintaining a constant temperature, but it doesn’t tackle the issue of moisture.

• The ideal temperature is between 22° and 25°C (71–77°F)
• Your growing environment should be damp/moist, but never wet
• Relative humidity range should be between 70% and 90%
• Seeds favour fluorescent lighting (Cool White code 33)
• Minimise the amount of seed handling you do
• In hydroponic/rockwool plugs, the ideal PH value is 5.8–6.2

Before we jump straight into the germination methods, there are a couple of germination golden rules. For the best results, we recommend staying within these guidelines, no matter how you choose to germinate. That being said, of all the factors to consider, temperature is one of the most critical. Seeds will always seek out even the smallest amount of moisture, but they use temperature as a sign that they need to do so.


Your growing pots will need to be placed in a damp climate that is within the temperature range listed under our golden rules. After 4–10 days, you should see a young seedling sprout, while the roots will have begun to develop underneath the soil. The entire plant and its soil can now be transferred to a larger pot, where normal growing routines should start.

Place one sheet of damp kitchen towel on a flat surface. Space your seeds a few centimetres apart before placing the second piece of kitchen towel over the top. You need to ensure both pieces are damp, not wet. Once again, when the white root tips reach 2–3mm, move the seeds (carefully) to soil pots. Use the same guidance found above for planting techniques.

Timescales can vary, as it all depends on how ideal your germination environment is (see the golden rules above). Even the worst grower could make a seed germinate, but it may take a few weeks and, of course, increases the risk of a weaker plant.

Two or three weeks after germination, your young seedlings should be ready for their new home. At this point you have two options; transplanting them into soil pots, or taking on the challenge of hydroponics. You’ll know when the seedlings are ready to be moved because the root system should start to poke out of the bottom of the wool blocks. As long as the roots haven’t begun to engulf the bottom half of the wool block, they will seek out water and nutrients in their new surroundings and continue to grow downwards.

You should also know that all of a vegetable plant’s growth habits like how large it gets, how healthy the plant is, and the size, quantity, and quality of the fruit produced is totally dependent on 4 main things:

The soil temperature must be warm enough around the seeds for them to germinate. If it’s too hot, seeds “cook”. If it’s too cold, seeds will stay dormant or simply rot. All vegetable varieties have an optimum range of soil temperatures for proper seed germination. Here are a few examples:

Adequate moisture is necessary because it is the presence of water that triggers the germination process for most seeds. Your seed starting mix should be pre-moistened and kept evenly moist, but not saturated through the entire process. Successful growers will also pre-soak seeds for 2 to 8 hours prior to sowing. Soaking will help initiate proper germination by allowing water to penetrate the seed coat. This is especially helpful for seeds with thick, hard seed coats.

Common Seedling Problems

Remember, all seeds have the same simple mission; to break dormancy, put down a simple root (radicle) and send up their seed leaves (cotyledons). This is all a seed can do with the energy it has stored. The rest is up to you, the gardener, to make the new seedlings happy, continue to grow, and thrive. Manifestations of “bad seed” are poor or no germination. Under proper conditions, if the seed germinated…it was not a bad seed. Rest assured seed companies thoroughly and continually test their seed lots for germination. We try to maintain seed lots that will test higher than national standards allow. This means we are shipping some of the healthiest, freshest, and most viable seeds available.

If these three requirements (moisture, temperature, and air) are met, and fresh seed is used, you should get a high germination rate. If your seed germinates, and then your seedlings die, this is not because the seed is “bad”. All a seed has the capacity to do is germinate. That’s it!

The most optimum temperature for seed germination is in the middle of this range. Tools needed to achieve proper soil temperatures are simple but necessary. Use a soil thermometer and employ use of a good Seedling Heat Mat, for seed germination success.

All a seed can do is germinate. A child born to doctors will not automatically have the capacity to become a doctor. Give your seedlings the same care and nurturing you give to your children; plenty of sun, elbow room, air to breath, proper nutrition, and moisture. Weak, spindly plants will not reward us with adequate flowers or fruit and plant diseases will latch onto them quite easily. We all need as much optimism as this spring can bring, for our seeds and of course for our children. Remember, gardening is a noble, intellectual, and passionate pursuit that anyone can do, but it all starts from an ordinary, humble sleeping seed.

You will need a container that is two to three inches deep and features holes at the bottom, for drainage purposes. The width of the container can vary – it all depends on how many seeds you wish to plant. However, remember to ensure you leave enough room for the seeds to germinate. You can buy trays from your local garden centre or online, or you can even use an egg carton. Now that you have your container ready, you will need to line your seeds with your growing medium. Do not fill your container right to the top with this combination, instead leave approximately half an inch at the top. Lightly wet with water to provide a good environment for the seeds to grow in. However, do note that soil-less mixture contains zero nutritional value so it may be a good idea to use seed and cutting compost.

Some seeds may require soaking before you plant them, whereas others do not. Make sure to check all the information on the packet as previously mentioned. If your seeds do require soaking, you will need to do so for several hours before adding to your growing medium.

2) Learn About Your Seeds

A seed is defined in the dictionary as being ‘the unit of reproduction of a flowering plant, capable of developing into another such plant. We recently spoke about how plant cells grow and how to sow seeds indoors , so we thought we would expand on that a little bit.

Now, that you’ve got your seeds ready – you will need to plant them. It is possible to plant seeds both straight away directly in your garden soil or alternatively in containers that can then be transported outside further down the line. This decision depends hugely on the species you wish to plant as some require more sensitive care than others. To do so, you will need to know the ideal growing conditions for your plant; the germination time, and also the earliest time from which you can transport your plant outside.

You can purchase propagators which are designed for growing multiple fruit or vegetables from seed. These containers are perfect for the task at hand.