The Basics Of Growing From Seeds

Growing Seeds

Plants have been growing in soil long before humans started gardening, having a myriad of ways to spread their seed, using animals, insects or even the wind. During this time seeds grew with no human interference and a balance of species thrived. So why now does it seem tricky to grow from seed? Why do we sometimes struggle with growing our plants? Here’s a few handy tips and insights into growing seeds in a soil based medium.

Why aren’t my seeds growing?

There are a few reasons why, when growing seeds, germination and sprouting won’t occur. Most of them coming from human interference.

  • Seeds have a shelf life. Use them as soon as possible to increase their chance of growth. However, make sure the germination environment is suitable for the plant to grow in.
  • Seed coatings (Testa) often need soaking to soften or scratching (scarification) to help it to break open and germinate. In the wild this would happen with weathering or animal interference.
  • To initiate biological processes, most seeds need a warm environment.
  • Sown seeds need plenty of moisture. The water content of the seed needs to be about 70% for a chemical process to start.
  • More exotic seeds have dormant periods that can last years. Or require unusual conditions to break their dormancy such as fire.

How much/often should I water my seeds?

This question is not as straightforward as it appears. There are several factors which determine how much and how often you should be watering when growing seeds. But ultimately it comes down to experience and judgement.

The first key factor is age. Seedlings need moisture and humidity. Their root systems are too small to draw up enough water if their leaves lose too much to the atmosphere. However, too much water/humidity can lead to damping off (pythium). So careful monitoring with a hygrometer (humidity monitor) and ventilation to keep the levels between 50-70% is desirable.

As the seeds grow, watering levels should increase. Whilst different genus and species of plants require different levels of water, a decent wet/dry cycle will be suitable for most plants. This means drenching the soil with water and allowing it to dry. When growing seeds in pots, pick the pots up to check their weight after watering. As the soil dries, the pot will get lighter. Try to wait as long possible before the plant starts to wilt, to water again. After the first cycle you will have an idea of how long it takes and use that as a guide.

Over/under watering issues are the most common questions we receive here at Plant Magic. The big problem is that people don’t often see them as watering issues. This is because when the roots can’t access air and water, they can’t uptake nutrients properly. As a result, leading to deficiencies, which people report as such and blame the nutrients, without finding the root cause.

Balance is key

As a rule of thumb, your soil should consist of:

  • 45% minerals
  • 5% organic matter
  • 25% air
  • 25% water

This means if you’re growing seeds with a 10L pot, about 2.5L of water is needed. However, to account for moisture already in the soil, between 3 and 4 litres is a good place to start.

Growing Seeds Graph

This should give you plenty of run-off (water draining from the bottom of the pot) leaving your soil fully wet. This not only replicates a natural rain shower, but as the roots intake water, the rhizosphere dries out and the roots then spread out in search of more water. This expands the rhizosphere, giving bigger roots with more potential to absorb nutrients. As the rhizosphere dries out, air replaces the water allowing the microbes and the roots themselves to respirate. If the soil isn’t allowed to dry or becomes waterlogged through poor drainage, many microbes die.

How do I mix nutrients?

This is a simple question that comes up from time to time. First, work out how much water you need, and using the guide on the packaging, how much nutrient to use. Always give yourself a little bit extra to account for spillages etc. Next weigh/measure out the nutrient. The less nutrients you’re using, the more important it is to be precise. A 1ml error in 5ml is 20% whereas a 1ml error in 50ml is only 2%. Add nutrients to your water and mix thoroughly. All nutrients should be 100% soluble. Some will take longer to dissolve or mix up depending on their composition. Because of this, always spend some extra time making sure it’s an evenly mixed solution.

When using two-part nutrients like our Coco A & B, or using additives, always mix in between adding each part. The reason nutrients are separated or come with additives is that certain minerals react with each other in high concentrations and become insoluble. This means they’re unavailable to the plant and can block hose lines and pumps. However, once diluted, they’re fine to use. So, by mixing in between adding them to your water stops these precipitation reactions.