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The start your plants get determines their health, their robustness, and the yield you’ll get from them. Get the seed starting bit wrong, and your crops will fail. Seed starting is easy, but it’s also easy to get wrong, so we’ve put together this practical guide to seed starting for beginners to help you get the most from your growing space. Yes, it’s true that you can buy transplants, plug plants, and potted plants, including vegetable crops, but it’s insanely expensive, you have no control over how the plants have been grown, and they still may not produce healthy, mature plants. So bite the bullet, save yourself lots of cash, and start your own seeds, even if you’re a total beginner.
1. Know When to Plant
This is one of the biggest mistakes beginner seed starters make – planting too early. It’s a fatal error. When you start seeds too early, they have to stay indoors for longer. This leads to bound roots and/or weak, leggy seedlings. Bound or compacted roots result in weak plants that aren’t particularly healthy and are at risk of pest infestation or disease. Leggy plants are weak and most likely won’t mature. So don’t get over-excited, and don’t get fooled by those first few sunny, warm, transitional days in late winter and early spring. Do your research. Don’t just be guided by what it says on the back of the seed packet, either – make sure you find out the best planting times for your particular area or hardiness zone.
2. Know What Seeds to Start Where
We’re mainly talking about edible plants and companion plants here, because we’re more about growing healthy, natural food than pretty flowers to fill a vase with. The first rule: Don’t start root crops in trays or indoors. They don’t transplant well, if at all. If you try and start carrots, beets, and parsnips in trays then transplant them, they’ll either fail altogether or you’ll get weird, deformed crops. Peas, beans, and corn also don’t always do well when started in cells. Having said that, some varieties do reasonably well started in large pots or cells where there’s plenty of room for their roots to develop without getting bound and stunted.
With some crops, it’s possible to get a jump start on the growing season by planting the first sowings indoors, early – providing you transplant them regularly as they grow and provide the right soil and temperature conditions. We do this with heat-loving crops, cool-season crops, or those that are slow to mature:
- Winter squashes
- Spring cabbages
3. Seed Quality Matters
Don’t skimp on your seed quality. Remember how much money you’re saving over buying transplants and plug plants, so don’t go too cheap on the seeds. Go with reputable seed suppliers such as those who perform extensive germination tests and field trials. Shop for varieties best-suited to your local conditions. Talk to other growers in your area and ask for recommendations. And, where possible, go to local seed swaps or buy from regional suppliers – here you’ll often find the varieties that have adapted to conditions in your region over multiple generations.
High-quality seeds and those strains adapted to your local area grow faster, have a better germination rate and, if you treat them right, produce healthier plants with a bigger crop yield.
4. Choose Your Containers for Starting Seeds
What should you use to start your seeds in? Cells, flat trays, or blocks? Well, the choice is yours. Ideally, you need 2 to 3-inch deep growing medium. For small seedlings that need regular potting on like tomatoes, peppers, and broccoli, small cells or plugs are adequate. For larger seeds like pumpkins and melons, or seeds that do best when undisturbed, like beans and sweetcorn, use deep, roomy flats or single pots. Blocks are made by compressing starting medium using a soil blocker. Each block acts as its own container, so requires no pot or cell.
You can also get a little creative and use whatever you have to hand. Make cylinders from newspaper, stand them in a tray or on a hard surface and fill with compost. These are easy biodegradable seed starters, as are toilet roll and kitchen paper rolls. Once your seedling is mature enough, you can simply plant the newspaper, loo roll, and kitchen paper roll pots directly into the ground. Repurpose small plastic containers like yogurt pots, milk containers, and similar by punching small drainage holes in them and using them as pots. You can reuse these year after year and prevent these plastics ending up in landfill or polluting our oceans.
5. The Right Planting Medium for Seed Starting
Not all planting mediums are equal. Remember, seeds require moisture and nutrients to thrive. Beginners often make the mistake of just grabbing a bag of peat-based compost from the garden center without any real consideration. To give your seeds the best start, you need a loose, well-drained mix that’s nutrient-rich. While it’s true that peat-based mixes drain well yet retain a reasonable amount of moisture it’s just not a sustainable choice. Peat is super-slow growing so is considered a non-renewable resource. Plus, peat is harvested from peat bogs, which are complex and diverse ecosystems, and the harvesting destroys that ecosystem, wiping out huge swathes of habitat for flora and fauna, and putting multiple species at risk of extinction. As of 2018, peat is being harvested over 200 times faster than it forms – which is a pretty scary statistic.
Therefore, we’d never recommend using peat-based seed starting mixes. Instead, make the responsible, ethical choice and choose a renewable and environmentally friendly mix that uses something like coir, which is essentially coconut hair. This all-natural coconut by-product is a great alternative to peat moss. It provides the same porous texture and is actually easier to keep consistently moist. It’s super easy to make your own mix – and usually less expensive, too. All you need is one-third coir, one-third organic compost, and one-third organic topsoil. Just make sure, if you use your own compost, that it’s mature and that it’s reached a high enough temperature to kill off any weed seeds.
6. Feeding and Watering Seeds the Right Way
The key to giving your seeds the best possible start lies in the preparation. A couple of hours before you want to sow, take your seed starting mix and stir through enough water to make is uniformly moist. Now don’t go crazy and soak it so much that you end up with a sodden slop – it just needs to be thoroughly moistened. Then use this pre-moistened mix to plant your seeds in. Once you’ve finished planting, cover the trays (or whatever you’ve planted your seeds in) with plastic wrap or a sheet of clear glass or perspex. This will hold enough warmth and moisture to induce germination. As soon as sprouts appear, remove the cover.
Don’t be tempted to drench your seedlings. If you keep them too wet, they’ll rot. Use a mister to gently water from the top when the soil feels dry to the touch. The other option is to water the empty tray beneath your cells.
If you’re using a nutrient-rich seed starting mix, you shouldn’t need to use any fertilizer unless the seedlings have to stay in-situ for an extended period before planting out. You can also choose a seed starting mix that already contains an organic fertilizer. If you want to give your seedlings a nutrient-boost, dilute a high-quality organic fertilizer and add to the water in the empty tray beneath your cells. Check out our post on 9 organic fertilizers you can make at home without spending a penny for money-saving homemade fertilizers.
7. Avoid Damping Off When Starting Seeds
Damping off is a fungal disease that attacks seedlings and is a direct result of too much moisture and humidity. If damping off occurs, you can’t save affected plants – all you can do is remove them and their compost and hope to save the remaining plants, which is not always possible as it spreads quickly. So, it all comes down to prevention. The least expensive way is to control heat and moisture – don’t over-water and ensure you provide adequate ventilation, particularly during hot weather. Once your seedlings are up, open the door or vents every day for at least four hours during the hottest part of the day. If you know damping off or prolonged high humidity is going to be a problem for you, you can also apply a 0.5-inch layer of light sphagnum moss across the top of your ungerminated seed starting containers. It’s reasonably inexpensive and holds 20 times its own weight in water while still allowing plenty of air flow. It also harbors a number of different bacterium that prevent the occurrence of some plant bacterial and fungal infections.
8. Light and Wind Make Strong Seedlings
Aside from water and nutrients, your seedlings need plenty of light and air to grow strong. While you can’t necessarily expose them to wind, what you can do is gently run your fingers over the tops of the seedlings to simulate wind and to encourage strong stems. As mentioned above, make sure you provide adequate ventilation to avoid too much humidity and the onset of fungal issues. And lastly, seedlings need light. More light than a mature plant. If you notice them getting “leggy” – long, thin stems and small leaves – your plants aren’t getting enough light. And, to be honest, if they already look weak and significantly leggy, they’ll never mature into healthy, high-yield plants. If you’re using a greenhouse or polytunnel, make sure you put it in a position where it gets plenty of natural sunlight. If you’re growing indoors or in a more shady area, you’ll need grow lights. You can also use regular fluorescent bulbs. You’ll get the best results – the healthiest plants – by providing between 14 and 18 hours of light each day. You can automate this by putting the lights on a cheap timer.
As I mentioned, seed starting isn’t that difficult, but it’s easy to go wrong, even for experienced gardeners. Whether you’re brand new to starting your own seeds or a veteran, put some of these tips into practice for healthier, more robust plants that are naturally more resistant to pest infestation and disease. And healthier plants result in higher yields of larger, healthier crops.
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