There are a lot of different ways to successfully start seeds. Here’s some tips and information that work for me. I’ve written it for planting vegetable seeds but I use the same methods for all other seed types as well.
- I start my seeds in my cold, drafty basement using fluorescent lights on a timer. While it sounds less than ideal but it has proven to be an excellent growing environment. Some plants may not grow as quickly in a colder room, but they still grow.
- If you think about it, seeds in the wild start under all sorts of weird conditions where it seems impossible but it works. So don’t think you need a perfect setup to get started. Things tend to work themselves out despite us. If they didn’t, humans would have perished long ago.
- The basic needs for germination are adequate amounts of moisture, heat, and, eventually, light.
- Pots and containers
- Soil blocking tool. You can see how a soil blocking tool works here.
- Fluorescent lights hanging on chains with S hooks, and digital timer
- Shelving unit
- Growing medium for seed starting, and/or compost and soil
- Christmas rope light
- Plant tags
- Pen and paper for notes
- If you don’t have the time or space to experiment, start with seeds you know are fresh and viable. Always read the seed package. The seed supplier wants you to like their seeds and provides any information they can to help you grow healthy plants.
The information on the seed package should also tell you
- any preparation the seeds need, such as presoaking or chilling in the fridge before planting, or scarifying (scratching the seed surface)
- how deep to plant the seed in the growing medium
- whether the seeds like warmth or cooler temperatures, and lightness or dark to germinate
- when to plant the seeds in relation to your estimated last frost date
- how long it should take from seed (or planting outside) to harvest
- Seed starting dates are calculated based on when you want the young plant ready to be planted outside. Your seed package will have a suggested schedule, usually based on the estimated last frost date in your area.
- My What To Plant When Chart lists all of my planting dates (indoors and outdoors) as well as recommended companion plantings and crop rotation groups (for healthy soil and thwarting pests).
Containers and Soil Blockers
- I use whatever I have on hand: plastic pots, food containers from the grocery store, peat pots (before I knew peat was a contentious issue), and soil blocks.
- The soil blockeris my top choice because there’s no plastic or waste, and I won’t have to transplant the individual seedlings. This tool squishes the potting mixture into a compressed, standalone block, and leaves a middle hole for inserting the seed. Clever! All of the soil blocks can be placed on a waterproof tray under the grow lights. You can see a demonstration and more details here.
- Don’t combine different seed types in the same container or you’ll have a problem with varying heights under the grow lights. The tall ones will be too close and the shorter ones will get leggy trying to reach so high.
Soil or Growing Medium
Commercial Growing Medium
- In North America, a lot of gardening advise says to use soil-less mixtures specially formulated for starting seeds.
- If you do use a commercial growing medium for seedlings, make sure it is organic or food safe. Read the ingredients. You will be eating food from this soil, after all.
- A common recipe is 1 part each of peat or coconut coir, vermiculite, and perlite. All of these items come with environmental concerns and plastic packaging. Gardening is not very green at times.
- In the UK, I see a lot of compost and potting soil used for seed starting. I find it gets expensive to buy bagged mixtures and sometimes use my own compost and soil instead. I have really good germination rates and get healthy plants so this it’s worth trying if you want to keep costs down.
- Before planting, I mix my planting medium with water to get a consistency where it will form a ball in my hand but not drip with excess water. This is the right consistency for using the Soil blocking tool as well. Seeds seem to like this level of moisture. If you dampen the mixture after the seeds are planted, they can float away.
- Before starting, I decide which seeds I will plant and enter them in my spreadsheet.
- I also prepare my plant tags first so they’re ready to use as soon as the seeds are planted. I also have an easy no-tag seedling tracking system you might like.
Frugal Heat Mat
- I use a Christmas rope light coiled under my seedling containers to warm them during germination. They give off just the right amount of warmth without any danger of fire or overheating. CAUTION Before you try this, makes sure the type you choose are safe to leave on 24 hours a day for a week or two. I will assume no reponsibility for your actions.
Fluorescent Grow Lights
- Most seeds do not need light until they have germinated. That’s when they get placed directly under the lights with the timer set for 12-16 hours a day.
- You want the light positioned not more than an inch above the tops of the sprouted plants. They lights provide light but very little warmth.
- I use fluorescent shop lights (48″ long with 2 bulbs each). The bulbs are T8 type and I put one ‘warm’ bulb and one ‘cold’ bulb in each unit, which creates a ‘blue’ light. There’s more on my grow light setup here.
- When the basement is really drafty, I hang blankets over 3 sides of the plant light shelves to keep the air warmer. This way there’s still air circulation but the temperature stays in more reasonable range. Most plants want to be in an environment of 60-80 degrees Fahrenheit. And so do I, for that matter. Some people also run fans to circulate the air, and deter white flies.
- Sometimes seeds just do not germinate, or, they start and suddenly stop growing and die.
- I like insurance in numbers by planting essential crops like tomatoes in new, smaller sets every week or two.
- The same seeds might not flourish in week one but take off like gangbusters when started in week three. Fertility is a mysterious thing. And, unfortunately, seemingly, rather random.
- I do not fertilize my seeds or seedlings. Seeds actually come with all the nutrients they need to grow from seed through to the first seed leaves, called cotyledons.
- The first true leaves come next, and that’s when the plant becomes hungry for outside nutrients and a soil with compost is warranted. Because I often start seeds in compost, I don’t have to worry about this. Alternately, you may want to use an organic fertilizer to give growth a boost.
Write It Down
Make notes of everything you do so you can figure out what works best for the future. I keep a spreadsheet noting:
- the name and source of the seeds
- how I prepared the seeds
- date planted
- when they started to germinate (how many days it took)
- when I transplant the seedlings to pots
- how the plants do under the grow lights
- when I start hardening them off (introducing them to the outdoors, a few hours a time)
- when they were planted in the garden and I add an outdoor plant tag telling the dates I should expect the harvest
- when the plants were ready to eat
- any pests, diseases, or problems encountered
- best ideas and tips for next time
Caring For the Seedlings
- Check the plants each day to note any changes and make sure the growing medium is moist but not sopping wet or dry.
- I try to keep a bucket of water sitting out so it can off-gas the chlorine for a few days before I need to use it.
- It’s best to water from below, with all the containers sitting in drip trays, instead of watering from above which can cause problems with seeds or seedlings floating away or moulds or fungi forming. Yummy!
Potting Up and Thinning Out
- Prepare your notes and have your plant tags ready before you start potting up.
- When seedlings have their first 1-2 sets of true leaves, after the initial cotyledon leaves, they are ready for a richer soil and a larger container. If you’re using soil blocks, you can move the entire block and seedling into larger soil blocks or plant them in containers.
- Seedlings should be handled by the true leaves, never the stems. I find the replanting of seedlings to be the most fussy part.
- Some use a pencil or chop stick to gently make room for (poke a hole in the soil) and then guide the seedling into the new pot. If you’re good at this, you should be a surgeon.
- Fall and winter crops are started from seed midsummer. You want to time it so that the plants are established before frosts set in. Hoop houses and row covers can protect many cold-loving plants all winter long.
Saving and Storing Seeds
- I keep my seeds in the cool, dry, dark basement. I have envelopes arranged in alphabetical order by plant type (you can see my simple system here).
- Throughout the summer and fall, and collect seeds from my garden to try planting the following spring.
- I mark the stems of favourite flowering plants like poppies and delphiniums to make sure I collect the seeds from those specific seed pods.
Sow, grow, eat, repeat.