Growing from seed is both challenging and rewarding. While most new gardeners prefer buying seedlings I am a firm believer in jumping right in and starting your seeds yourself. While the probability of failure is much higher than with seedlings; once you learn how to germinate seeds at home it will not only build confidence but also save you a lot of money in the long run. Seeds are much cheaper than seedlings and you will have more flexibility around what you can grow. However, there are a few things to consider and we will cover them all in this article. My goal for this article is to explain everything you need to know to germinate your seeds at home. Our first step is choosing the type of seeds you would like to grow.
Table of Contents
Choosing your seeds
Choose an open pollinated seed variety
Whenever I am looking for seeds Open-pollinated varieties are always my first choice. Open-pollinated basically means that the pollination involves something external to the plant itself (this could be wind, birds, insects etc.).
Open-pollinated plants are genetically diverse and its genetics can change over time. Because of this plants can slowly adapt to local growing conditions. This means, even if I buy seeds that weren’t originally adapted to my climate, I can eventually end up with a seed stock that works well for me. As long as pollen is not shared between different varieties within the same species (e.g. peppers), then the seed produced will remain true-to-type. Therefore, using open-pollinated varieties will allow you to save your seeds and grow quality produce, adapted to your environment, year after year.
Heirloom seed varieties
When you are purchasing seeds you will probably also come across the term heirloom variety. This basically means the seeds were passed down in a family or small community. An important distinction is that all heirloom variety seeds are open-pollinated but not all open-pollinated seeds are heirloom varieties.
Hybrids and GMOs
I typically stay away from hybrid and genetically modified seeds. Neither option allows me to save the seeds from the fruit they produce to grow that plant again. Hybrids don’t grow true to the original plant and well…if genetically modified seeds grow at all they don’t produce good fruit….but I guess that was the point, right?
A note about organic seeds
It is common to hear someone ask for organic seeds, I’ve done it myself because that’s the common terminology people use to describe seeds. However, the word you are probably looking for is open-pollinated.
By definition, organic seeds are produced by flowers and have been grown without the use of man-made chemical fertilizers or pesticides. To be certified organic, crops must also be raised in a sustainable manner, with care taken to improve the health of the soil. Organic seeds can be open-pollinated or hybrids (but they cannot be the result of genetic engineering, i.e., the insertion of DNA foreign to the plant). Therefore, it is very possible to buy a hybrid, organic seed and not have it grow true to the original plant.
Choose a seed that will grow well in your climate
Plants should always be grown in (their appropriate) season. This means, if you aren’t 11 degrees north of the equator like I am (where it is hot ALL the time) you should be especially careful not to choose varieties that are early spring or fall crops. When choosing a seed consider not just the temperature today, but the temperature range you anticipate your plants will be growing in over their lifetime.
Most seeds have a minimum and maximum growing temperature which is usually indicated somewhere on your seed pack. Try to stay within that growing range as much as possible. If you have someone producing seed locally they will be your best option because the seeds will already be adapted to your region.
Choose a disease-resistant variety
Choosing disease-resistant varieties can save you the headache of a disease problem before it even starts. If you are growing and saving your seeds disease resistance is going to be dependent on the genetics of your plants. However, in most cases, resistance is specific to a particular disease/ plant issue. A cucumber variety that is completely resistant to powdery mildew can be severely affected by leaf spots. As a result, it is important to know which disease problems are most likely to affect you.
Direct sow or indirect seeding
When you are starting your seedlings you will have to decide if you are going to start them directly into the ground (direct sow) or plant them into a container (usually a seedling tray) and transplant them later. I almost always choose to start my seeds in a container and then transplant them later. Being able to move my seedlings inside during heavy rains has made the difference between me having a bountiful harvest some weeks later or starting from scratch. Indirect sowing allows for more control over growing conditions and gives your plants and soil greater protection from pests. For this reason, the success rate for indirect seeding is higher than direct seeding, and will therefore yield a greater crop.
The only time I may choose to direct sow is if the plant matures very quickly (like radishes, which will mature in about 28 days) or if the plant roots really don’t like being disturbed and are sensitive to transplanting (such as carrots). If you are direct sowing using the square foot gardening method using their seed gridder can come in handy to ensure your seeds are properly spaced.
Choosing a Container to start your seeds
While there are many standard seedling trays available a DIY option can work also. When choosing a container you should generally choose a shallow (about 3 to 5 inches in depth) container. The depth of your container is the most important part. If your container is less than 3 inches, the roots will touch the bottom too soon it will stunt the growth of your plant.
When choosing a seedling tray try to get one that is made of durable plastic so that you can use it over and over again for years with slits some on the sides of it to air prune the roots of your seedlings. There are also biodegradable options available which are great because in most cases you can plant the entire cell with minimum work shock.
In this article, I will refer to what you are growing in as your growing medium rather than soil. Soil has a very specific meaning. As it’s common for seeds to be germinated in a soilless system (eg peat moss coconut coir etc) it’s a good habit to not confuse the two.
When choosing your growing medium to start your seeds the soil you already have in your garden soil shouldn’t be your first option. Most garden soils have insects that will feed on the roots of young plants. Also, if your soil isn’t well balanced the microorganisms found in the soil can actually inhibit germination.
Ideally, you want to pick a medium that will give good airflow to the roots while holding moisture. Choosing a sterile medium such as peat moss or coconut coir will increase your chances of success since there is very little chance of unwanted bacteria or insects coming affecting your seedlings. Coconut choir will always be my choice over peat moss purely from the aspect of sustainability. For my seeds, I use a mixture of 1/3 compost, 1/3 coconut coir and 1/3 pearlite. Compost is important to provide seedlings with the nutrition they need after germination and since I made it myself I made sure it was well-aerated and has the right type of microorganisms that won’t damage my seedlings. Coconut coir can hold 8 times its weight in water but can dry out fairly quickly on its own. Perlite absorbs both water and air, roots need both water and air to grow strong healthy roots
If you are looking for a commercial seed starting medium Promix or any commercial seed-starting potting mix will work well. Most companies making these mixes commercially have their processes so you get a good result every time. A word of caution though, Promix is for seedlings, not soil. In our experience mixing it into your garden soil will damage your soil structure. Our soil didn’t absorb moisture well (because peat is naturally hydrophobic) soon after the Promix was introduced and the plants absorbed the nutrients it contained. It took an extremely long time to break down and get the soil back to what it used to be.
Starting your seeds
Setting up your trays
To start your seeds the first thing you will need to do is to fill your container. Fill your containers to the top if it’s a standard growing tray or at least 3 inches if you are using a non-standard container.
When planting a seed you want to plant it at a depth of about 1.5 times the length of the actual seed. Most gardeners recommend planting 2-3 seeds per cell to ensure at least I plant germinates out of each cell. However, if it’s a compound seed like beets or swiss chard that has multiple plants per seed, planting one seed per hole is ok. Cover the seed lightly with your growing medium either by simply pushing the soil that was displaced when you made the hole over to cover it or (as I prefer to do) just sift or sprinkle some soil on top gently. My reasoning for preferring the latter is so that when the seedlings sprout the soil they have to push through is a lot less compact. Give the tray a deep water.
To ensure each cell has an adequate supply of water over time I prefer using a watering tray. The water gets taken up by each cell as needed and I don’t have to worry about watering too heavily and disturbing the growing medium on the surface.
Germinating your seeds
Germination is the growth of a plant contained within a seed after a period of dormancy. Once all goes well the result of germination is the formation of a seedling.
When germinating your seeds you should try to keep them in as controlled of an environment as possible. If you are in a colder climate you can try using a heated pad under the germination try to keep the seeds warm. If you get heavy rainfall like we do keeping your germinating containers under a well-lit shed or under some shade netting to protect them from the elements.
In the first phase after germination, the plant has all the nutrients it needs in its seeds. The first step of germination is a process called imbibition (absorption of water), which is usually what tells the seed to start germinating. It’s important to supply adequate and consistent water to seeds. One of the easiest ways to do this is to place your seedlings in a watering tray and use a humidity dome.
If you are germinating your seeds indoors humidity domes can be very useful. They generally help protect the seeds and keep the moisture in their immediate environment even. Your seeds will germinate without it, so it isn’t a necessity but it is a good option to have it you are trying to increase germination rates. A simple DIY option would be to use a container with a clear cover that is 3 to 5 inches deep. Put a few holes at the bottom for drainage and line the bottom with newspaper. Fill the container with at least 3 to 5 inches of your growing medium and cover the container.
Whichever option you choose, removed the cover once the seed starts to sprout. Seeds are in the germination process they require constant moisture. However, once sprouted, this same humidity can lead to mould, so be sure to get them uncovered once the sprouting begins.
For seeds, respiration begins once imbibition has occurred. Once the seed has germinated oxygen is needed. Your growing medium should be as wet as a well-wrung sponge. If it is too wet the roots won’t get the oxygen it needs and the seeds will likely rot. This can also happen if the temperature isn’t correct for the seeds you are trying to germinate.
Sprouted seeds need light and air circulation to thrive at this point. Your seedling tray should be moved to somewhere with access to sunlight or grow lights and good air circulation. If the seedlings are put under lights too late they can get leggy and may not mature well.
Poor germination can happen for a number of reasons. Some of the reasons your seeds may not be germinating well are:
- Viability of the seeds. Not all seeds are viable. Germination may not occur if the seed are old or expired. The length of time a seed will remain viable depends on the genetics of the seed itself and how well that seed was stored.
- Microbial make-up of your growing medium. Some soil microbes can inhibit germination. This is especially true if the soil is not balanced or has more anaerobic bacteria and fungi present.
- Insects in soil. Some insects (such as sow bugs) love eating new seedlings. Having these in your growing medium will significantly affect your germination rates. This and the previous point is why we stressed so heavily on having a known, controlled medium for starting your seeds, and not starting your seeds using garden soil.
- Wrong temperature. Temperature is an important factor in activating germination. Most plants require a 25-30∘C temperature range to germinate properly. However, some may need to start off in the fridge to stimulate germination and then be transplanted after. If you believe the temperature is your problem check the information on your seed packet or reach out to your seed supplier for more information.
- The soil is too wet. If the soil is too wet an adequate amount of air won’t get to the roots and the seedling will die off and rot. Roots need some air to “breathe”
- Inconsistent moisture during germination. If the moisture in your medium isn’t consistent or is left to dry out while the seed is germinating the seed may not have enough water to survive. This will lead to the roots dying off before it is able to get established.
If you are using a purely sterile environment there won’t be any nutrients available. If you’ve gone with any standard seed starting mix the manufacturers have already solved this problem for you. When a plant first germinates all the energy the plant needs is inside the seed. After germination, the plant needs to get its nutrients from the environment around it. Only after the seeds have germinated and the leaves begin to develop do the plants begin to take up nutrients from the soil or medium around it. The First Leaves give the plant the opportunity to reach out and begin photosynthesis, then it starts needing more carbohydrates and starts putting out true leaves. When the plant starts showing its true leaves you then see the plants identity.
Liquid fertilizers such as compost teas are the easiest way to fertilize if there aren’t sufficient nutrients in the medium for the seedlings available.
There are many suitable liquid fertilizer options available. I like making a fresh batch of compost tea from by earthworm castings and I use that to water the cells. The worm tea is rich in beneficial microbial life and gets my seedlings off on the right track. This also ensures any of the undesirable bacteria I may have in my
compost will be suppressed, thus improving my chances of success.
When to transplant your seeds
To determine when it’s time to transplant have a look at the bottom of the trays. If the roots are growing through the bottom or if the roots are getting root bound in the cells then it is definitely time to transplant your seedlings in the ground or in a larger container. If some of your seedlings are further along than others just plant the strongest ones. Some seedlings may have germinated a bit later than other but that’s ok, these can be used to replace any of the plants that don’t make it later on.
At this point, you can use a more traditional soil mix. Transplanting should be done early morning or evening when the soil is generally cooler weather.
So you’ve gotten to the point where you have your seedlings and you are ready to transplant. If you are like me, space is limited and you need to grow as much as possible in the space you have. The Biointensive growing method gives the best option to get the most out of your space by planting on a diagonal is going to be way more efficient than planting in a straight line (see image below). If you are interested in planting on the diagonal one of the easiest ways to do this is to purchase a sheet of chicken wire (chicken wire has a hexagon pattern), making a frame and use that as a grid to space your seedlings. If you need a spacing wider than the wire will allow, you can do it by eye and mimic the pattern of the 5 on a dice. What you are aiming for is to space your seedlings (or seeds if you are direct sowing) far enough apart so that their leaves will barely touch when your plants reach maturity.
When plants are properly spaced they form a sort of living mulch that retards weed growth and aids in the retention of soil moisture by shading the soil.
How to transplant your seedling
When you are ready to transplant your seedlings consider the following steps:
- Remove the seedling from its container. When transplanting your seedlings hold the plants by the tips of their leaves, or by the soil around their roots, never by their main stem. The stem of the seedling is very delicate and it is very easy to damage your seedlings if too much pressure is applied.
- Gently spread the roots apart. This is especially important if you notice the roots have started to wrap around itself (i.e. the plant is becoming root bound). Loosening the roots encourages them to grow in all directions and form a good foundation for the plant.
- Prepare the hole for planting. Dig a hole large enough so that the seedling can be buried up to its first set of true leaves. Burying them as described prevents the plant from becoming top heavy and bending over during their early stages of growth. Many plants(such as tomatoes) have tiny hairs on their stem. Every one of these fine hairs are a potential root (tomatoes are a good example of this). When you bury the plant deeper more roots will develop along its stem.
- Lightly compress the soil around the plant. This is just to ensure the plant roots are in contact with the soil. But don’t press so heavily that the soil becomes compacted and the roots can’t get any air
- Water your plant. Right after transplanting give your plant a good water. Aside from your plants needing water to grow, watering will encourage the plant’s roots to grow into the soil further helping the plant settle firmly into its spot.
- Add Mulch. Adding a thin layer of mulch will not only provide some protection to the soil while the plants develop it will also protect your plants. During heavy rain or watering with a watering can soil can easily splash on the leaves of your plants. This can lead to plants being infected with soil-borne diseases. Therefore, adding a layer of mulch is just one additional step to take along the way.
Despite your best efforts some seedlings still may not make it after transplanting. Nature will eliminate unhealthy plants and the weaker seedlings will be the first to be attacked by pests and disease. If you have any additional seedlings left use them to fill any spaces that result in your planting area.
Once you have transplanted out of your seedling trays it is good practice to sterilize your equipment. You can do this by washing them in warm soapy water first and then giving them another rinse with a hydrogen peroxide solution. Sterilizing your equipment is important so that any harmful bacteria aren’t transferred from one batch of seedlings to another. Store your containers out of direct sunlight in a cool dry place.
Starting your seeds yourself can be a process initially. It can take some trial and error to get into a successful rhythm of doing things. Even then, things will go wrong every once in a while. However, learning this skill will pay off a thousand times over once you are able to grow the food you need and save the seeds from your harvest. The next time you plant you will have a seed that is slightly better adapted to your local environment than the one you started with.
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