What You Need to Germinate Seeds Successfully

Simple tips to help you germinate seeds, whether you are sowing them indoors, or directly into your garden

Peat pellets macro closeup on black tray for potted plants containers by window on table for growing tomato and peak indoor garden seedlings during winter
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In order to get the highest possible yields from your garden, it can be helpful to go back to the fundamentals and take some time to really think through the process of growing plants from beginning to end.

Growing your own means making sure that you understand the needs of your plants, and the environment in which they are grown. When you get things right, it can be a truly rewarding experience. But when growing at home, not everything will go according to plan.

One area where things can often go wrong is during seed germination. Many new gardeners don't really take the time to consider what this process requires. So here are some simple tips to help you germinate seeds successfully, whether you are sowing them indoors, or directly into your garden.

A Good Garden Needs Good Seeds

First of all, in order to achieve good germination rates, you need quality seeds. Of course, you can save your own seeds from heirloom or heritage crops. But if you are buying seeds, you always need to consider the source.

Make sure you choose seeds from a reputable supplier. And, ideally, source seeds from as close to home as possible. Seeds lose viability over time, and if stored or transported incorrectly, can yield poor results. Make sure the seeds you choose are suitable for growing in your area, and in your particular garden. (Check with your local cooperative extension service for advice on what may be, or may not be, suitable for your area.)

Good Germination Rates Depend on Environmental Conditions

Once you have your seeds, remember that you too will have to store them correctly. Then you will have to make sure that you provide the seeds with the environmental conditions they need to germinate successfully. Even when the environmental conditions are not perfect, you can still get plants to grow. But boosting germination rates by optimizing conditions can increase the yields possible from your garden.

Here are some important things to think about when trying to make sure conditions are ideal:

Water Requirements For Germination

Mature seeds typically need to rehydrate. This means that they will take on significant amounts of water before they can begin the germination process. As the seeds take in water, hydrolytic enzymes are activated. These begin to break down the food stored within the seed so that metabolic processes can take place. Water also softens the seed coating, allowing a seedling to emerge.

The amount of water required will depend on the type of seed you sow. Water too little, and germination cannot take place. But water too much and this can also cause a range of issues. Water needs tie in with the next requirement – oxygen. Ensuring that both water and oxygen needs are met is crucial in ensuring good rates of germination.

Seeds Require Oxygen For Germination

Before seeds develop leaves, most of their energy comes from aerobic respiration. In other words, seeds need oxygen from their environment for metabolic processes to take place.

When insufficient water is supplied, the coatings on some seeds may not be able to break down. Sometimes, this is necessary in order to allow seeds to take in water and oxygen from their environment.

But overwatering can cause waterlogging and compaction. Which can mean that seeds are starved of the oxygen they need.

In terms of oxygen needs, it is also important to make sure that seeds are buried to the right depth. If a seed is buried to deep, this might also make it more difficult for oxygen to reach them. (Some seeds also need light for germination, and so must be placed on the surface of the soil.)

Make sure to consult the seed package or information elsewhere to check how deep to sow and other requirements for the specific seeds you are planning to geminate.

Choosing The Right Growing Medium

An important part of making sure that water and oxygen needs are met is choosing the right seed starting growing medium. The potting mix that you use for general purposes, or for mature plants in containers, will not necessarily be suitable for seed starting.

A seed starting medium can either be soil-based or soil-less. But it will usually need to have a finer texture than a typical all-purpose compost or potting mix. The texture and structure of the mix must remain moist, yet be free-draining enough to prevent waterlogging and compaction. Though if you are sowing seeds to pot on or transplant fairly quickly, it does not need to be particularly high in nutrients.

To keep your gardening as sustainable and eco-friendly as possible, make sure you choose a peat-free option. Peat is a valuable carbon sink and its ecosystems are crucial in maintaining biodiversity and the world's water cycle. It cannot be naturally replenished as fast as gardeners are using it. So we should leave it where it is, protect those precious ecosystems, and use alternatives in our gardens.

Homemade Seed Starting Mix

The most sustainable option is often to simply make your own seed starting mix. For most of my seeds, I use a mix of:

  • 1/3 homemade compost
  • 1/3 leaf mold
  • 1/3 loam (garden soil)

However, you can also make a soil-less mix to make sure you avoid issues with fungal diseases like "damping off," and weeds. Composted woody materials, or coconut coir, are materials often used for this purpose. It is best to try to choose locally available materials to reduce your negative impact where possible. But always keep the basic environmental needs of your seeds in mind.

Seeds Need the Right Temperatures

As well as thinking about oxygen and water, and the growing medium that provides optimally for these needs, you also need to think about temperatures. Where and when you plant is crucial to make sure you provide the right temperatures for germination.

Most common annual crops have a minimum germination temperature of roughly between 36 F and 60 F degrees, but also have optimal ranges. Optimal germination temperature ranges can vary significantly for different crops. For example, parsnips will germinate best between 50 F and 70 F degrees. And, towards the other end of the range, aubergines will germinate best between 75 F and 90 F, tomatoes between 61 F and 86 F, and peppers between 64 F and 95 F degrees.

When sowing indoors, heated propagators may be required for best results for warm-season crops, depending on the temperatures inside your home. When sowing outdoors in cooler climates, sowing too early can result in much lower germination rates. So these are very important things to think about if you want to achieve the best possible results.

There is, of course, a lot more to learn about the specific requirements of different seeds. But thinking about these basics will point you in the right direction for getting the best germination rates possible, and get your garden off to a good start this year.