You can get started starting seeds at any time of the year. Indoor, and outdoor seed starting is a useful, money-saving garden skill to have, and to know. There are many different techniques for starting seeds, and a few finicky to start seeds, but most seed starting is simple.
Depending on your location, March is either late winter or early spring. This is the best month for starting seeds, either indoors if it’s still late winter for you, or slowly starting to get seeds started outdoors if it’s early spring. Seeds give you a wider range of varieties and sub-types of different plants to try. While a bedding plant supplier may have five to ten types of tomatoes, a seed supplier may have thirty or even fifty varieties to chose from.
First off, your seed package should have some information on seed starting on it. Most seeds come with information on how long before your last frost date you should start them. Some seeds can be started outdoors before the last frost date, others need to be started indoors before the last frost date.
Your last frost date will depend on your zone and can be as early as April or March, and as last as mid-May or even the start of June. Consult a Farmer’s Almanac, or your local gardening groups for more accurate last-frost information for your zone. You can also have local variation on the last frost date depending on your individual yard’s micro-climate.
What you Need: Starting Seeds Indoors
Indoor seed starting starts a lot sooner than outdoor seed starting, unless you do winter sowing. We’ll cover winter sowing when we cover outdoor seed starting later in this post.
The first thing you need for seed starting is the seeds you want to start. Indoors, we start seeds like peppers, tomatoes, eggplant, and other heat loving and frost intolerant crops. The very first seeds to start include hot peppers and onions, starting up to 10 weeks before your last frost date, and herbs like rosemary and thyme and some flowers. This is also the time to cold stratify stocks, lavender, and other seeds that need cold stratification.
The second set of seeds at eight weeks before the last frost date includes all tomatoes, basil, sage, and other flowers like cosmos. Four to six weeks before the last frost date we start cole plants that head, like cabbage, broccoli, cauliflower, and Brussels sprouts.
Four weeks before your last frost, you can also start some squash, cucumber, luffa gourds, wax melon, watermelon, cantaloupe, and other sensitive rooted plants at this time. Plant them in larger containers, or large soil blocks for best results. This is also the time to indoor start corn as well, if desired.
You’ll need seeds for your plants of choice, and the varieties of those plants that you wish to grow. Richter’s herbs is a great Canadian source for herb seeds. Baker Creek is a good American source for heirloom and open pollinated varieties. If you think you may like to save your own seed, look for heirloom varieties, or at least non-hybrid ones. Many of the seeds you get in packets at the grocery store, hardware store, or dollar store are going to be hybrids.
Seed starting containers are the next thing. I prefer small pots made of sturdy plastic. The sturdy, slightly more expensive, plant starting pots will last for several seasons. Many people like using plastic solo cups for tomato starts, since it gives the roots a good chance to develop. Other recycled plastic containers can also be used. I’ve used ice-cream pails, yogurt cups, and even pudding cups for seed starting.
Bio-degradable pots can be used, but I prefer only using them for starting plants 2-4 weeks from my last frost date. This is because the biodegradable pots are harder to keep watered. The peat ones especially will pull all the water into the pot, and leave none for the soil and the seedling. They also will go moldy on the edges if there isn’t adequate airflow. Lastly, they still need to be torn and removed for planting, otherwise the plant’s roots will not penetrate from the pot into the outer soil. Many people like making their own seed starting pots from toilet paper tubes, egg cartons, or from newspaper. Just remember that these pots do need to be removed from the root zone for the plant to thrive.
If you prefer avoiding pots and single use items, soil blocks can be a good bet. You can make your own using a soil blocker out of your preferred seed starting mix, or potting soil mix. I like soil blocks for plants that shouldn’t have their root disturbed, like pumpkin, cucumber, melons, and luffa. Use your largest possible soil blocker for these plants. You can also transplant upward in soil blocks.
Peat moss pellets and coconut coir blocks are another option for seed starting. They do not have nutrients in the pellet however, and the mesh holding them together must be removed before transplanting out, or up-potting the plants. Coconut coir can also have a high salt content, which can stunt seed growth.
A combination of peat, perlite, and vermiculite is often used as a soilless mix. I prefer using regular potting soil as my growing medium, since it has some fertilizer added and I don’t have to worry as much about feeding my seedlings during the indoor phase.
I prefer using an organic potting mix. I’ve had the most success with using organics in this regard. When I have tried cheap potting soil, my seedlings were stunted or failed to thrive on transplant. A mid-range potting soil can work if you don’t know where to start. I normally just use potting mix from the get-go, and avoid using seed starting specific soil mixes.
After your seeds, soil, and containers, the next thing you need is light. A good south facing window can work to start a few seedlings. Maybe a dozen. So if all you’re starting is a few seeds, go ahead and use your southern windows for light. If you’re starting a 20+ plants, you’ll want adjustable grow lights. Full spectrum florescent shop lights are also used, for large seed starting set ups.
Lastly, if you’re starting hot peppers, or other heat loving seeds, you’ll want a plant heat mat with a thermostat control.
Setting Seeds Up For Success:
Set up a seed starting space that is protected from toddlers, and cats. A small indoor greenhouse can work, or a sturdy table. I use my seed starting table both to hold the starting plants, lights, and heat mat, and as my workspace for planting seeds and potting up seedlings.
While you can start lettuce, kale, spinach, chard, dill, marigold, calendula, and peas in advance. I prefer direct planting these, as well as root vegetables like carrots, turnips, and beets. See further down the post for the outdoor seed starting segment.
Start with dampening down your potting soil. If the soil is super dry, I use just-boiled water and pour it directly into the bag. If the soil feels damp, you can add more water once the soil is scooped into your starting pots. Make plant markers out of Popsicle sticks, or use plastic plant markers.
Plant your seeds into your prepared pots following your seed packet depth instructions. One or two seeds per-pot is a good number, even of small seeds like tomatoes. Most commercially sold seeds are germination tested, and should give you up to 90-100% germination rate. Exceptions may be labelled as “over packed due to low germination” with the expected germination percentage. If it’s below 40%, plant three seeds per pot instead of two to make sure you get at least one plant per starter space.
Place your pots on trays, and cover lightly with a plastic cover to keep moisture over the seeds. You can use plastic wrap supported by your plant labels. Set your light fixtures over the trays. If desired, sprinkle cinnamon over the soil surface to prevent fungal growth during the germination phase and decrease the chance of damping off disease.
Monitor your seed trays until the majority of containers have at least one sprout. Remove the humidity dome in stages. And keep your soil surface moist during the transition.
Some growers recommend adding a small fan near your seedlings to imitate wind movement and help them develop roots, and stem strength. Others brush their hands over their seedlings a few times a day, for the same purpose.
When your seedlings have 1-3 sets of true leaves you can plant them up into larger pots. Tomato plants can be planted deeper, in their new pots with soil going up the stem. They will develop new roots along the stem. Other plant varieties should be planted to the same depth as they were in the seedling tray.
Most seedlings like 12-16 hours of light, so put your fluorescent light fixture, or grow lights, onto a timer. The seedlings can also have direct sunlight from a window, if desired. However, if growing in a windowsill remember to turn the plants, daily, so they don’t develop a lean and legginess toward the window.
This is the most important step of your seed starting journey. It’s the step that will make sure your seedlings thrive in your garden.
Start hardening off on an overcast day, when there’s no danger of hail, heavy rain, or high wind. Place plants outside, on their trays, for about 15 minutes. Then bring back indoors. Each day, increase the time outside by 10-15 minutes, as long as the plants don’t seem shocked, wilted, or droopy when you bring them back in. If the day will be sunny, place the plants in a shaded spot until they’ve built up to two hours. Then let them start getting sun for those two hours, and gradually increase the in-sun time by 30 minutes until the plants are outdoors all day.
Once plants are in full sun, they may need extra watering to ensure they don’t dry out during the day. Or, place water in the bottom of their trays when placing outside.
After the plants are outdoors all day, if you still have danger of frost, you’ll need to keep bringing them inside, or place them in a cold frame overnight.
Seed Starting Outdoors:
Prepare your outdoor garden area, either in-ground, raised beds, or containers. Check your seed packets for outdoor planting information and timing. You’ll want seeds like peas, beans, lettuce, kale, chard, orach, radishes, and carrots for your early season planting.
Peas can be planted outdoors up to 2 weeks before your last frost date. Sow them in rows, about 4″ apart and 1/2″ deep. Check if your peas are bush type, if they are not labelled as bush peas, they will vine and could use supports or a small trellis. The trellis supports can be added after the peas are 2-4″ tall.
Radishes and carrots can be planted at the same time. Some people interplant radish and carrot seeds because the radishes are faster growers, and will serve as a marker for the carrot row. When the radishes are harvested, it leave space for the carrots to now thrive. Sow in rows about 2-4″ apart, and try to space seeds about 1-2″ apart. Sow carrots thinly along the radish row, if planting them together.
Lettuce and mescalin mix can be planted in closely spaced rows for leaf harvest. For head harvest, plant lettuce on a 4″ square, or lightly scatter seeds over a few square feet and plan to harvest young lettuces to thin them out to the 4″+ spacing.
Around your last frost date, directly plant corn, beans, squash, and cucumbers. Even if you’ve started some indoors, you can also plant a few seeds outdoors and compare the results. I prefer protecting the seeds with a plastic cover or floating row cover until germination occurs and we’re at least 2 weeks past the last expected frost date. This helps with germination. I would not recommend directly planting watermelon or other melons, they do better started indoors.
If you have a compost pile, it can be a source of hardy volunteer plants. Tomatoes, eggplant, pumpkin, and many other seeds will volunteer in the compost pile, a little earlier than they’d volunteer to grow in the garden. Transplant any of these you want to grow, or let them grow in the compost and see what they give you.
Check out this post for growing garlic.
I have slow growth and purple stems of tomatoes, peppers, and heat loving plants, what’s wrong? Usually this indicates a minor nutrient deficiency, often related to the ambient temperature. While tomatoes and peppers can grow at 65F, they prefer it to be at least 70F consistently. If your house temperature shifts low at night, and only is in the high sixties during the day, then you may get purpling stems and leaves due to the temperature preventing some nutrient uptake. Placing plants on temperature regulated heat mats, or on a table over one of your room heat sources, like a vent or baseboard, can help.
Soil is waterlogged and plants are failing to thrive. Let the soil dry out, and make sure your pots have functioning drainage holes. If you’ve made your own plastic pots, make sure there’s at least 3 stabbed holes in the bottom of the pot. If using commercial pots, make sure that there’s no plastic blocking the holes. The commercial pots don’t always have the plastic punched all the way out.
Outdoor planted carrots are not germinating? This is usually due to a moisture issue. Cover the row, if only planted with carrots, with a board or other sun blocker. Leave in place for a day or two, and check underneath. The soil should remain damp. Once the carrots begin to germinate, remove the sun block and let grow. A good mulch along the edges of your carrot rows can also help.
Overwhelmed? Start Simple
All these different plants can be both exciting, and overwhelming. There’s so many options, seeds, techniques, and research black holes to fall into. So, to start, start a few seeds for a plant you love. This could be as simple as starting a snapdragon, calendula plant, or even basil or another herb. Or, it could mean starting four different cherry tomato plants. Start with something you love to eat, and learn to grow it.
If you don’t have space for even a few containers, you may still have space for microgreens and the space and ability to grow your own salads – all year round!
New to growing food and vegetables?
Check out the Fill Your Salad Bowl workshop and learn how to use 3 different growing methods, at home, so you can fill your salad bowl with super food, nutrient dense, greens every single day. These are greens you can use in your salad bowl, greens you can add to soups, stews, and pasta dishes, and even greens you can use in a stir fry.
In this mini workshop you will learn how to fill a salad bowl every day with food you grow yourself.
- Even if you don’t have any land.
- Even if there is 3 feet of snow covering your garden
- Even if you’ve killed house plants in the past.
- Even if you think you have a black thumb.
Have a look at what’s covered in this workshop and see if its a good fit for you, by clicking/tapping the blue button below.
Leave a Reply