Growing your own seedlings has many benefits, including:
- It can be better value, as a packet of seed, some pots and seed raising mix can cost less/ produce more, than buying seedlings (saving your own seed, reusing pots and making your own seed raising mix can save you even more)
- An exciting wide range of unique varieties to choose from that you may not be able to source as seedlings, and this way you can help protect biodiversity
- Reduce negative impact that can be associated with packaging, distribution and production of conventional seedlings
- Be resilient against possible food shortages or price rises, or food distribution issues, by knowing how to grow from seed
- It is satisfying and enjoyable hobby
- You can connect with other seed savers
There can be challenges, including that it does take more time (to actually pot up the seeds, but then also waiting weeks for them to grow big enough to transplant), you need somewhere to raise them with the right conditions, and there may be poor germination rates, pest issues etc.
Seeds for growing veges and herbs need the right amount of warmth, moisture, light and oxygen to help them to germinate and grow. To create the right conditions to germinate the seeds, and support the growth of the seedlings, you will need:
- Seed Raising Mix (fine soil which retains moisture, is light and airy, and has some nutrition to support the growing seedling)
- Mini pots, seed trays or other containers
- Sunlight (12 to 16 hours a day of good quality light)
- Water (using a spray/ misting bottle, or small watering can/ bottle with fine nozzle)
- Seeds (bought, saved or swapped)
- Labels/ labelling system
You will also need time to set up, learn the skills, and possibly troubleshoot when growing seedlings.
PLANNING + GETTING STARTED
What seedlings you want to raise, and how many, will be influenced by the time, budget and space you have in your garden, as well as your growing climate/ zone. If you cater for more than you think you need, you can always give them away (or sell them) if you do end up with an oversupply.
- Decide what system you will set up, i.e. which containers you will source or buy, if you will set up a mini greenhouse (or even invest in, or build a full size greenhouse at some point)
- Decide where to locate the seed trays/ mini greenhouse on your patio/ windowsill/ laundry (somewhere with decent sunlight and ventilation, where you can easily keep an eye on them, but also, that won’t be affected by any water leaks)
- Make a plan of what and how many seedling you want to raise, based around what is suitable for your space, time and family preferences/ requirements
- Make a list of the equipment and materials you need to source, and gather them
- Plan a day, or weekend, to put it all together
- Set up your containers, and add the seed raising mix
- Pot up your seeds, and gently water
- Ongoing maintenance and troubleshooting, leading up to transplanting
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There are many types of containers or set ups, that you can use to raise the seeds, for transplanting.
- What is it? You may keep and use pots that previously purchased seedlings have come in. You may be able to buy pots, or ‘seed trays’ second hand at a tip shop, or find them on a buy/ swap/ sell group. Of course, you can buy new plastic seedling pots at the hardware store or nursery. You can also get seedling trays to hold the pots.
- Benefits reusable; stackable for storing; can get decent amount of seed raising mix and water into them, drainage holes already in the bottom; you can write a label directly on them with a chalk pen
- Challenges cost to buy new; some people may not like growing in plastic
- Considerations you may want small sized pots (55mm, like forestry tubes, or round mini pots), which take less seed raising mix and space, but can be limited by the seedlings outgrowing them. You might consider larger ones (100 – 200mm), which require more seed raising mix, but I start many of my warm season seeds in larger pots, as I know for my climate it will be many weeks until the frosts have passed, and this gives them the chance to really grow and thrive in my greenhouse, until it is transplanting time.
SEED TRAYS/ PUNNETS
- What is it? Punnets (AKA flats) are shallow plastic trays, with individual sections for one seedling, or seed trays refers to trays with only one large section that fit multiple seedlings in them. They have drainage holes in the bottom. You may keep and use punnets/ trays that previously purchased seedlings have come in. You may be able to get them secondhand, or you can buy new.
- Benefits space efficient; reusable; stackable for storing; you can write a label directly on them with a chalk pen
- Challenges cost to buy new; sometimes tricky to get the seedlings out of punnet trays
- Considerations you can buy punnets with just a few sections (6 to 8) or with many sections; you may buy these trays/ punnets with clear covers that fit over to make mini greenhouses
- What is it? pots that can be planted into the garden bed with the seedling, to reduce ‘transplant shock’ (by not disturbing the roots, and by slowly integrating to the garden bed as the pot breaks down), such as peat pots or coir pots, coco pellets, soil blocks, or newspaper/ origami pots, or egg shells or toilet paper tubes/ rolls
- Benefits less transplant shock; no need to store between seasons
- Challenges may include, that they dry out quickly; don’t provide a lot of support; cost for buying jiffy/ coir pots; seedlings may outgrow them before the timing is right to tranplant
- Considerations look into a wooden Pot Maker to roll your own newspaper pots.
OTHER POTS/ OPTIONS
- What is it? consider recycled and DIY options, like milk cartons (cut in half), yoghurt containers; egg shells and egg cartons, toilet paper rolls
- Benefits include affordable, eco-friendly, accessible
- Challenges include some options may require drainage holes put into the bottom; some may dry out quickly, or the seedling may outgrow them quickly; not reusable
- Considerations these are a great way to share your excess seedlings because you have not given away your pots that you want to use for the next season (or rely that people will return them to you); also good to use as an activity with school kids, or offer freebies at a fair/ expo
- What is it? you can buy various styles of mid-sized greenhouses which have layers of shelving & soft plastic zip covers that you secure to an outside wall or fence, or even set up shelving outdoors, with a simple plastic cover over it. Or you can buy mini greenhouses, which include a hard plastic cover that goes over seed trays/ pots, or make your own (using plastic covers from sheet sets/ quilts that you’ve bought, over pots, held up with wire coathanger or chop sticks/ small branches. You could also use large plastic storage boxes (with lids) either with the pots in them, or seed raising mix directly in the bottom (either drill holes in the bottom of the box, or do not overwater).
- Benefits keeps in moisture and warmth required for seeds to germinate and seedlings to grow; may be portable & easy to take outside (or open the plastic cover) when it comes time to harden off seeds
- Challenges be careful using boxes that the seedlings inside may not get enough sunlight and will grow leggy/ spindly, or may get too much heat and can become weak
- Considerations you may be able to buy a kit that includes the seed tray/ punnets with an exact fitting cover
OTHER EQUIPMENT/ MATERIALS TO CONSIDER
- Grow lights – make your own, or buy a system, that encourages growth with artificial lighting
- Heat Mats – electric mats or pads, that the seed trays sit on to boost warmth required for germination and growth
A NOTE ON Seed raising mix
Seed raising mix is a fine blend of materials that encourage the germination of seeds, and growth of the seedlings. It needs to retain moisture, but not become saturated or compacted. It needs to be light and airy, so roots can grow and breathe easily. It needs some nutrition, but not so much that it overwhelms the seedling. You may be happy to buy bags of seed raising mix, or you may want to make your own mix.
- To make your own, check out this article by Milkwood Permaculture, or these instructions from Organic Gardener Magazine.
- If you are going to buy it, remember that seed raising mix is not the same thing as potting mix (which is much coarser). It may be hard to source organic seed raising mix, or seed raising mix that doesn’t also include a chemical fertiliser or wetting agent.
A NOTE ON LABELLING
- You should label your seeds/ pots with the name, variety, and date. Don’t make the mistake of thinking that you will remember, or be able to identify once they are germinated/ grown! Plus if you use the date, you can keep on eye on the success of germination, i.e. if it hasn’t occurred within the expected timeframe, time to problem solve and pot up more seed! (Some people also use garden journals, or planners for that).
- You can use a variety of options, including reusable labels you can buy, or make your own from cut up plastic containers, like ice cream containers and lids, or milk cartons. Write on these with permanent markers.
- Another option is using chalk pens, which can be removed your reusable pots/ trays by rubbing/ washing them off, but test the chalk pen first to make sure it won’t come off with just water (I use one which comes off with a good rubbing and wash, but not when the pots are watered) – if you are using this option, you won’t have labels to put into the garden bed when you transplant, but you can create a ‘garden map’ instead
- A garden map is a way to know what you have planted and where in your garden beds, espescially if you have a bigger area. Draw a template of your garden beds, or use a word doc, that you can photocopy/ print and use each season to write your plantings.
Some varieties of vegetables and herbs only grow well by planting them as seed, directly into the garden bed where they will grow, as they do not transplant very well into the garden bed after germination occurs (they get ‘transplant shock’). These include carrots, beetroot, radishes, swede, turnip, beans, peas, silverbeet/ chard, spinach, corn, kohlrabi, coriander, parsley, dill.
Other produce can be either sown direct, or raised as seedlings and transplanted. What you choose to grow will depend on the space you have, the climate or zone you are in, what season it is or what you are heading towards, and what you eat. To learn more about growing ‘by the season’, please see the Beginners Guide to Edible Gardening.
In areas like Canberra, the warm season is quite short, so ‘extending the season’ means potting up warm season seeds and raising seedlings in advance (several weeks), which enables a head start once the soil has warmed up enough and the risk of frosts has passed, in Mid Spring.
I highly recommend checking out Gardenate (they also have an app) to work out what climate/ growing zone you are in for your country, and the guidelines for what is recommend for you to plant in what season/ month. You can see their suggestions on what can be sown direct/ potted up, and transplanted, and the timing required.
Easy to RAISE Cool Season vegetables & herbs
Pot up in late Summer to early Autumn
- Kale (Red Russian, Dwarf Blue, Curly, and Purple Scotch kale are mild kales)
- Onion/ Leeks/ Spring Onions
- Try in plantable pots: Sugar Snap Peas, Snow Peas, Peas, Asian greens
- Note: Broccoli, Cauliflower, Cabbage, Brussels Sprouts, take a little more attention to grow, but you can give them a try
Easy to RAISE Warm Season Vegetables & Herbs
Pot up in late Winter to early Spring
- Zucchini – dark green, but also look for golden scallopini/ button squash, golden zucchini, cocozelle (striped green) or Lebanese zucchini (pale green)
- Tomatoes – cherry or grape tomatoes (we like yellow pear cherry tomatoes)
- Basil – sweet Genovese is good for making pesto or putting on pizza
- Chillies – I like jalapenos and cayenne
- Capsicum – look for mini ones that grow quicker, and varieties like yellow or ‘chocolate’
- Try in plantable pots: Cucumber, Sunflowers, Pumpkin, Squash, Melons, Beans
- Note: Eggplant, Okra, and full sized tomatoes require a little more attention to grow, but you can certainly give them a go
Easy To RAISE Year Round + Perennial vegetables & herbs
- Herbs (chives, sage, tarragon)
OK, now that you have made your plans of how you will raise your seedlings, and what you want to grow, let’s get ready to pot up.
- seed raising mix
- containers to grow in
- hand trowel (or use a small pot, to scoop up seed raising mix into the containers/ pots)
- dibber (or use the end of a pen)
- gardening gloves
- watering can or spray bottle
- labels and pen (I use plastic ice cream containers and lids, cut into strips), or a chalk pen that doesn’t come off unless rubbed off
Some seeds need special handling before planting, to bring them out of dormancy, and induce germination. This information should be available on the packet, or do some research if you have saved your own seed. For example, some seeds may need soaking (for several hours or overnight), to remove a chemical coating, or scarification, which is ‘roughing up’ or breaking the coating.
- Line up all your pots
- Fill with seed raising mix to almost full
- Make labels (or write on the pots with chalk pen) for the number of pots you are allocating for that type of vege/ herb
- Make a small hole for each seed (with your finger/ pen) to the depth required
- Place the seeds in the hole
- Cover up with more seed raising mix
- Put a label in (or write on with chalk pen)
- Repeat for the other varieties/ type of seeds
- Locate in a sunny spot
- Gently spray or water each day or every second day, until the soil is moistened, not saturated
- Depending on the variety, they could germinate (start to grow and pop up above the soil) in as little as 2 days, up to 2 weeks.
GROWING + MAINTENANCE
- After the seeds have germinated, they will have little ‘seed leaves’ (see bottom photo below) which help feed and nourish the plant, then they form their ‘true leaves’ after that, at which point you can start to use a diluted liquid fertiliser (worm tea/ juice) once a week
- Check every day to second day, for progress on germination and growth, as well as observing for any issues (see next section on Troubleshooting)
- Keep the soil moistened, but not saturated, watering to the base/ roots area, rather than all over the leaves
- Consider covering the pot/ tray with clear plastic (like the thicker clear plastic packaging that comes around sheet sets/ quilts, with structural support like an old wire coathanger or chopsticks) to create a mini greenhouse
- Consider using a diluted worm tea/ juice, or liquid fertiliser as a boost, but if your seedlings become ‘leggy’ or long and lanky, which can make them weak, hold off on feeding them, as they may grow too fast for their roots to have developed (this can also happen if they get too much warmth, say in a greenhouse/ seedling tray or on a windowsill)
- If you put several seeds into each pot/ seed tray, you may need to thin, or ‘prick out’, any seedlings that are growing too close to each other (as this will inhibit quality growth if left too crowded) by removing some of the germinated seedlings
GETTING READY TO TRANSPLANT
- It may take several weeks from potting up the seeds, to germination, to then reach the size when the seedling can be transplanted. They need at least 3 to 4 ‘true leaves’.
- Other factors may included making sure the weather/ conditions are right outside (be mindful of weather forecasts, esp for late frosts in Spring), and when you have space in your garden beds (from the previous seasons crops before removed).
- If the seedlings are outgrowing their pots, but it isn’t time to plant them out, consider repotting them, into bigger sized pots.
- They may need a ‘hardening off’ period to acclimatise the seedling, before then planting out when the weather reaches the right conditions for the seedling to thrive. This means taking them outside/ removing the mini greenhouse covers during the day, and replacing or moving back inside at night, for several days. Incrementally increase the time spent outdoors/ exposed over several days.
- You may also use cloches once the seedlings are in the garden bed, to help them acclimatise.
- See the Beginners Guide to Edible Gardening for information on transplanting the seedlings into your garden beds/ containers.
If your vegetable or herb seed didn’t germinate, ask yourself these questions:
- When did I pot it up? Does it simply need more time?
- Did I bury the seed too deep, or not deep enough?
- Is the tray/ pot getting enough sunlight? Is it staying warm overnight?
- Is it getting enough water? Has it gotten too much (and possibly rotted?)
- Was the seed old/ beyond it’s Use By date? Had it been stored incorrectly? Can I contact the company for a replacement?
- Any pests or diseases? Could it have germinated already, but been eaten?
If your vegetable or herb seedlings are not thriving, ask yourself these questions:
- Is it getting enough sunlight, warmth & consistent watering?
- When did it germinate? Does it simply need more time to grow?
- Was the seed raising mix good quality? Does it need a gentle feed?
- Does it need plant feed? Is there competition for the nutrients?
- Any pests or diseases?
If your vegetable or herb seedlings have become lanky/ spindly, ask yourself these questions:
- Are they getting enough quality sunlight?
- Are they too hot & undergoing rapid growth spurts?
- Are they getting enough water?
- Are they too close together & need thinning?
- Are they getting too much feed/ fertiliser, causing rapid growth spurts?
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