Germinating Seeds 101: The Basics
Germinating seeds can seem a little daunting if you've never tried it before. Sometimes it seems easier to grab a few seedlings from the local hardware store — they're already growing so they'll be easier to care for, right? This can be true. However, starting your own plants from seeds is not only significantly cheaper, but it also means that there is a much wider variety of plants you can grow. Have you ever seen a Pink Brandywine Tomato at the store? What about a Sugar Baby Watermelon? There are countless seed varieties to choose from and the local hardware store will only ever stock the most popular (because they sell!).
Close up of Pink Brandywine Tomatoes
Here at The Aussie Seed Shed, we do all the research about how best to germinate your seeds for you. Each seed packet you order will come with full and detailed germination instructions. Do you have to follow these instructions to the T? No. Absolutely not! We provide these instructions so you can have the best chance of getting your seeds to germinate. We have had plenty of seedlings emerge unexpectedly from our compost bin (we like to call these plants "volunteers"), and these plants were certainly not sowed according to directions. Like most things in the world of gardening, there is really no right or wrong way to do something. What we can do, however, is share some thoughts and tips about how to germinate seeds with you — and once you know the basics, experiment at will!
Sugar Baby Watermelon fruit on the vine in a raised garden bed
Seed sowing depth
When I first started learning about how to sow our own seeds, I couldn't believe how different all the sowing depths for each variety were. Each seed variety usually comes with a recommended depth to sow your seeds. Generally speaking, you poke a hole in your prepared soil a few millimetres deep, pop the seed in the hole, and cover the hole in soil. I was out in the garden trying to guess whether the hole I had just dug was 5mm and whether I should go and get a ruler...
None of this is necessary, of course. In fact, we have actually now learned that you don't need to remember the seed sowing depth at all, as long as you remember this one thing:
SOW YOUR SEEDS 2X AS DEEP AS THE SEED SIZE
This means if my pea seeds are 3mm in depth, generally speaking, the seeds should be sown around 6mm deep. This information is fantastic to keep on you when you're sowing seeds: no more going back and forth looking at the packet of all the varieties you are planting.
Does the seed depth need to be perfect? No, but don't completely disregard the recommended seed depth. Seeds will still germinate if they are sown too deep. However, this means that the seedling has to fight through more soil before it can reach the sunlight (which is the plants food source, right?). Sometimes, the seedlings can run out of energy before they break the surface. And sometimes, all that fighting through the soil can exhaust the seedling and it may not grow to its full potential after that. Seeds can be sown too shallow as well. Since the top layer of soil can be prone to drying out, if seeds are sown too shallow, we run the risk of our seeds drying out too. Seeds that are sown too shallow can also be obtained by pests easier. Depending on your watering technique, your seeds may also wash away if they are sown too shallow.
Overall, will a couple of millimetres ruin my seedlings? Nope! Just remember to make a hole about twice the size of the seed. Approximate is totally fine.
Direct sowing seeds into an in-ground garden bed
Don't sow all your seeds at once
'Succession planting' is the concept of staggering the time you sow your seeds. The aim of succession planting is to have your plants ready to harvest in stages, instead of all your crop being ready to harvest at once.
Succession planting is great for the backyard gardener, because it means you could have a constant supply of food throughout the season. However, if you plan on preserving your food, then succession planting may not be right for you. It may be much easier to harvest all your crop at once and then batch cook or prepare the food, rather than doing smaller batches every week.
How do you succession plant your seeds? Sow a batch of seeds, then wait a week or a fortnight (depending on how much your family will consume), then plant another batch. Essentially, you can continue this process until there is not enough time for the plant to mature before the growing season for that variety ends.
Succession planting can also lower the risk of unsuccessful germination or losing your seedlings. For example, if you only plant a proportion of your seeds, and they don't germinate successfully, then you will still have seeds remaining to try again. Trust us — it happens! By sowing seeds in succession, if the first batch does not germinate, you have time and resources to identify the problem and try again. This is a great way to reduce the risk of losing your crop, especially for beginner gardeners.
At the beginning of spring, we planted multiple rows of radishes (with the aim to preserve them), and they didn't germinate. The weather was inconsistent, going from extremely dry, hot days, to pouring rain and storms in the afternoon (standard Queensland summer!). This inconsistency in watering, soil moisture, and temperature meant our radishes only germinated at around 40%. We waited for the weather to do it's thing, and then replanted our radish seeds with 100% germination success rate. So sometimes, you don't even know what is going to affect your garden! But if you succession plant, you lower the risk of losing your crop to the unexpected.
Seedlings in Jiffy pots
Should I sow direct or raise seedlings?
There is a lot to unpack in this question — it could probably be an entire blog post on its own! But it is definitely something commonly asked. The germination tips on our seeds will often (but not always) say "sow direct or raise seedlings", so which one should you choose?
Sowing direct means sowing the seed into its final position. This can mean in the ground, in a garden bed, or in a large pot. But essentially it means that the plant will not be moved. There are certainly advantages and disadvantages to direct sowing. First, sowing direct means that there is overall less work to be done, right? You don't have to continue to change the size of the pot or grow bag, once the seed is sown that's it. Second, it also means the plant is not going to experience transplant shock. Transplant shock is when a plant experiences stress from being uprooted and moved. Transplant shock can appear as many different symptoms: it can mean the leaves of your plant turn yellow, the plants can wilt, the roots may not develop, etc. Your plant may recover (it most cases they recover) or it may not. When you sow direct, you eliminate the risk of transplant shock.
Sowing direct also means that your plants are exposed to the elements from the beginning. This means they their climate is not going to change (as opposed to starting seedlings in a protected area and then moving them outside). They are more likely to handle the elements and become hardy plants when they are direct sown.
There are disadvantages to sowing direct as well. Sowing direct means (like we said before) that your plants are exposed to the elements from the beginning. This can mean your seedlings, when they are at their most vulnerable stage, are not protected. They could experience extreme temperatures, changes in soil moisture, pests and predators, as well as damaging weather like wind. You also have much less control over the soil temperature.
Another disadvantage is that you cannot start your seedlings early if you are tight on space in your garden. If you have a plant already occupying a space in your garden, you need to wait for that plant to be fully mature and ready for harvest, before you can harvest the plant and sow your new seeds. Raising seedlings eliminates this problem, as you can start your seedlings in a different location and plant them out once the older crop is harvested. Some sources say this can save gardeners 4 to 6 weeks growing time!
Essentially, raising seedlings indoors or in a protected area really gives you more control over the environment. You can control the temperature, light, moisture, and protect your seedlings from the elements, pests, and predators much easier when you raise seedlings. This is likely to give you a higher chance of your seedlings surviving.
Take home messages
Remember:
If you lose your germination instructions or you are unsure of how deep to sow your seeds, make a hole double the size of the seed itself (or come back to our website to find the info!).
To avoid disappointment if your seeds don't germinate, and to ensure you have crops ready to harvest all season long, consider succession planting.
If you are short on time, have limited predators, are experiencing good weather conditions and have pre-prepped beds, maybe you should sow your seeds direct.
If there are plants already occupying your garden space, if you are worried about the seedling survival rate in your garden, or if the weather has been unpredictable, maybe you should try raising seedlings.
Overall, there is no 'one-size-fits-all' method when it comes to sowing seeds. Each seed variety needs to be treated differently, and each garden set-up will require tailored sowing methods. Once you understand the basics of seed germinating, you can experiment with what works best for you and your garden.
