b) Dark seeds indicate fungal attack. A whitish substance is visible fungal mycelia. Fungus spreads under cold, wet, & anaerobic conditions. Several combinations of factors can lead to seeds rotting: poor soil quality (infected, bad pH, or high EC), pre-soaking seeds in water, substrate is too wet, substrate is in a cold environment, and/or excessive high humidity caused fungal growth in substrate (due to humidity dome/propagator, pots covered with plastic, poor ventilation).
Choosing the correct soil for germination and seedlings should not be difficult. However, some growers feel overwhelmed and insecure by the seemingly endless jungle of products, whilst others may live in countries with a very small and unsatisfying range of products. Please refer to our SOIL GUIDE for tips and recommendations.
Some or all seedlings grow weak and tall
Poor germination results can only be the result of negative outside influences after purchasing the seeds and are beyond our control. This does not necessarily mean that the grower is at "fault". Even the most experienced grower can run into unforeseen problems such as fungus infected soil, a technical malfunction on an EC meter, etc. Often growers buy the wrong soil because it is recommended by the manufacturer or retail store (consult our Soil Guide for more info).
You can use a humidity dome/mini-greenhouse as a tray for germination but you must keep the lid half-way open or completely seperate to ensure fresh air exchange and humidity levels below 50%.
If all else fails, there are still a few more aggressive tricks that should only be used when, after a few days, your seeds have failed to hatch and make their way into the world.
For those beginning with the glass of water, the second step would be to move the seeds, after 24 hours, to the wet paper towels. Germination normally takes between 48 and 72 hours, and, in the case of old seeds, can last up to 5 or 6 days, or even weeks. Therefore, transferring the seeds to wet paper gives you more peace of mind, as you are dealing with less water and, if they open, they will not quickly drown.
For example, you can scrape off the outer layer of the seed with a little sandpaper, creating micro-abrasions that should let some water in. So you don’t overdo it with this scraping we have a little trick: roll up a piece of very fine sandpaper, with the rough side on the interior, and secure it with tape. Place the seeds inside and cover the openings with your hands. Then just shake it for a couple of minutes and the sandpaper will do its job. Another more risky option is to use a knife to cut the seed transversely, ever so slightly, which will help the water penetrate the shell.
Other good choices for germination
If you have only saved the seeds for a year and a half, they should not give you any problems. After this time period, even if you have stored them properly, germination may be more complicated because the older the seeds are, the harder their shells, so the water used to open them will take longer to penetrate them. Therefore, the first method to try to get the plant’s embryo to develop is to put your old seeds in a glass of water, with a few drops of hydrogen peroxide, for 24 hours. Hydrogen peroxide softens the shell and facilitates the water’s infiltration.
There are growers who prefer their seeds to germinate directly in the soil. In this case, in addition to ensuring that you have light and well-nourished soil, you can choose to dilute 10 ml (a teaspoon) of fulvic acid per litre of water, and use it to water the site where you have planted the seed. Another option is to use slightly carbonated water, as the additional CO2 will help the liquid penetrate the seed, causing it to germinate. It is also possible to use enzymes or germination enhancers, designed to help seeds open and develop in those first stages.
For all this you will need an airtight container or canister, or an opaque plastic bottle in which, in addition to the seeds, you should place little pouches of silica gel, to reduce the moisture. With regards to the best place in your refrigerator, the crisper is a good choice, as it is a little warmer than the rest of the fridge. Also, one last tip: if you store several strains in different bottles, it is a good idea to label them, so that you won´t have to open them to see which is which when you decide to plant them.
First, you have won half the battle if you were careful with the original storage. Seeds must be kept in a cool, dry place. Therefore, the best option is to store them in refrigerators at a temperature between 6 and 8 degrees Celsius, and with relative humidity levels between 20% and 30%. And sheltered from light, of course.