Winter in our area isn’t over yet. The last frost day is still a few months away. But spring is coming and with it the next growing season! Starting seeds indoors is the start of a new garden season. For a schedule when to start seeds go here, there is also a free printable that you can use to remind you when it’s time to start seeds indoors.
Why start seeds indoors?
We mainly start seeds indoors because of our short growing season. This way we can extend the season upfront. While it is still snowing outside, we grow young plants inside to transplant into the garden as soon as the weather permits.
In warmer areas, seeds do not have to be started indoors, a propagating greenhouse or even a cold frame might be a better option since it also has more optimal light. The idea is to have a place that is sheltered and somewhat warmer than the outside, to get a head start for seedlings.
Even in our cold climate seeds can be started outdoors using winter sowing, I find though that it has some limits in a cold climate. Read more in winter sowing works in zone 3.
Growing plants from seed is a lot of fun. I am always amazed, how out of a dry little something (seed) a new plant grows and produces delicious fruits that contain the same seed to produce new plants.
To start plants from seed also saves money. It isn’t a lot of work, but you can start a lot of seedlings yourself for the price of buying one plant.
What do you need to start seeds indoors?
Pots
Seed starting pots or propagation trays come in all sizes and shapes. If you want to avoid plastic you can also build your own pots out of newspapers or avoid pots altogether by using a soil block maker. There are also peat moss pots available, but from our experience, they don’t work so well. Maybe because our climate is too dry.
We use small planters (often recycled from plants we have bought here and there) for plants that are not staying inside long: like cabbage, onions, or lettuce.
For peppers and tomatoes, we mostly use the (free) yogurt containers. It seems like they have the optimal size for those plants and save me some replanting work.
Recycled toilet paper tubes make great planters for cucumbers. They can be planted with the seedling into the ground, so you don’t disturb the roots.
For squash and bigger plants, we use a bigger container so that the roots have more room to grow and are not disturbed by transplanting.
Propagation seed starter trays are great if you just want a start on plants like lettuce, chard, beats etc.
As in most cases with gardening, we encourage you to keep things simple and doable. Plants will grow in whatever pots you start them in. If you want to be specific, you can, but there is no real need for that.
The one thing that we would recommend is sturdy planter trays. They do make life easier to handle many seedlings at once. We also grow microgreens in them in winter, so it sure is worth it to have them.
Potting soil
The seed starter potting soil is important. You want good light soil. Special seed starting mix or soil that is very fine and sterilized, might be important for some seeds that are very small and hard to start. For most vegetables, we simply use a potting soil mix.
For sowing seeds in seed trays to prick them out later, you can use vermiculite instead of soil. We have a whole blog post about it, to learn more go here.
Make your own potting soil, Mel’s Mix from the Square Foot Garden book. Mix together: 1/3 compost, 1/3 vermiculite, and 1/3 peat moss.
You can find all of these ingredients in a garden center or Home Depot. Read more about the DIY container soil here.
We don’t recommend using enriched potting soil. The chemical fertilizers only give the plant a very fast start, but then the plant tends to ask for more.
Seeds
We have lots of information on getting seeds for the new growing season. As well as plant varieties we grow in our short growing season. Please follow the links to read more.
Labels
Labeling is important so you know what varieties you are actually growing. It does not matter what kind of labels you use. Garden labels are great, but a plastic spoon works just as well. Also, a garden notebook is a helpful gardening tool.
Grow lights
For germination, a seed needs moisture and nice warm temperatures, but not so much light. As soon as the seeds are up, young plants need a lot of light.
A south-facing window might be all you need. Starting seeds later in the season (see the planting schedule), helps with better light conditions, so that you might not need grow lights. Note that any natural light is better than grow lights.
An east or west facing window would be better with supplemental light. A north window is not a good choice for seedlings.
With a grow light you can start seedlings anywhere in the house, and it also helps to supplement the light you have so that the seedlings don’t become spindly. T5 lights are good for that.
Heat Mat
As we already mentioned seeds need warm temperatures to germinate, so find a warm spot in your house. The top of a fridge would be a better place than a cold but bright window. Placing the tray on top of a heating vent in the winter is great too. You want about 85F degrees for fast germination. A Germination Station with Heat Mat can be helpful.
After germinating not all seedlings like it warm. Winter crops like the cabbage family like it rather cool. We find they do better in a sunny basement window or out in the garage greenhouse. Check out winter sowing for cold weather crops as well.
Sowing seeds
Fill a container with soil and compact it down slightly. You want your container to be filled without air pockets, but also not too compacted. If the soil is dry, now is a good time to water. Make sure the soil is moist before planting the seeds.
We usually do not sow seeds in seed trays to prick them out later, it’s just one more step of work, and why do more if you don’t have to. But it is an option too.
Plant seeds no more than 3 times their size deep. Since we are indoors, they can be planted even more shallow. Only peas and beans do better well covered. But we usually don’t start them indoors anyway.
Plant 1-3 seeds for plants that grow best alone, like lettuce, tomatoes, and cabbage. Once the seedlings are up and growing, thin them out to have just one plant. See also what to do with multiple plants in one seedling for more options.
Onions, beats, and reddish love growing together as a cluster, you can start 4-6 seeds in one pot of them.
After the seeds are covered spray them with water. In our dry climate, we also like to cover the pots with plastic wrap to keep moisture in.
We do have a separate post for starting tomatoes from seeds, and safe ourselves even more transplanting work.
Do you like to start your plants from seeds or would you rather buy seedlings?
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I really want to start some seeds inside. I love to watch things grow. And you make it look so easy.
Well, it is easy ;). The main thing is – Just do it. I need to start some more too. So lets go to work!
I’ll have to figure out a window I can keep the dog and cat away from LOL Last week Taffy jumped at something she saw outside and ran smack into the window. That would have really messed up any plants I had there LOL
Keeping plants from pets is not easy. Good luck with it!
This is good information. I’m really enjoying your site. I will be spending more time on it.
Thanks for Sharing at Green Thumb Thursday.
Hugs,
Valerie
Glad you enjoying it! Thank you for hosting!
I always start seeds indoors, but usually end up buying some seedlings too. I live by the cutest nursery and never can resist the rows and rows of plants!
~Lisa
I hear you, going to nursery’s is so fun, plus some plants just don’t start so well at home (maybe it’s just an excuse to buy them ;)).
I hear you loud and clear on not being patient enough to wait. I usually start some seeds too soon, but that gets it out of my system. I started hundreds of hot peppers last month, leeks, edible flowers and am starting tomatoes tomorrow and the brassica family out in the unheated greenhouse tomorrow. It’s always reassuring to read other people’s posts to keep inspired and know we’re all on the right track. I’m frustrated by our -17C temp prediction for tonight – grrrr.
-17C is to cold for my liking. But what can we do, right? WE just go with the weather. My cabbage is up and growing in the greenhouse, tomatoes have to wait. I now have the Tower Garden, that helps a lot, since I can grow year round.
I started some seeds yesterday! Onions, leeks, peppers. These all seem to take a long time to germinate in my house (wood stove – different heat zones) so I start them first. I’ve got 17 different kinds of peppers! I guess I got a little pepper happy when ordering seeds (in my defense, my daughter bought some of them, and they keep a few years so I’ve got a bit of a stash). The next thing I’ll start is parsley, celery, some annuals, sage, cabbage, cauliflower, brussels sprouts, broccoli, tomatoes, more flowers . . . more veggies, more herbs . . . my kitchen will soon be a mini-greenhouse.
That sounds like a happy kitchen to me. Love how you adjust the schedule to your needs. It is hard to give seed starting dates that are exactly for any situation. Usually it is the experience that teaches us when and how to do things. And I get the pepper happiness ;).
Very informative article. We haven’t had a garden for the past 5 or 6 years, but planning on it this year. It’s a lot tougher to grow a garden with much success here in Montana than it was when we lived in Nebraska. This planting calendar is just what I’ve been looking for – Thank you!
You are welcome! Growing in cold climate is different, but once you get it, it’s just as much fun.
Living well above the tree line I always start with seeds. Up here were no vegetables grow naturally, the big benefit of seeds is having absolutely no insect pests: the insects here haven’t developed a taste for them yet. I heard, though, of a greenhouse in the North West Territories where some people brought in flats, resulting in a huge insect infestation.
Tomorrow I sow just a couple of brussel sprouts – the grow well here but the season is so short the sprouts are about the size of Skittles. I’m thinking this extra early start might produce a couple of meals in September.
Interesting that the bought seedlings had more insects. Here I often see the opposite happening and it makes me wonder what those seedlings are watered with. One of the reasons I like to start my own.
Thank you for the clear, concise information! I also live in a northern cold climate and need to extend the growing season. I get a little confused by the different infrastructure and systems with seed starting. For example, do seedlings need to go from indoor light racks to an outdoor greenhouse and THEN into the ground? Or can they simply go from indoors into the ground (once hardened off of course. What is the main function of a green house: for starting seeds or just as a “holding place” before they get planted outdoors? Then maybe could be used for heat loving summer crops like tomatoes, peppers and sweet potatoes? I live in northern Wisconsin zone 5A. Sorry to ramble and thank you for any direction you can offer. I love your site!!
That is a great question. You do not need a greenhouse for seedlings. But it is easier to harden them off in a sheltered location outside. Read more about hardening off plants the easy way. Even though we do have a greenhouse, it does not play a significant role for seedlings. Sure we use it some since we have it, but the main function of our greenhouse is to grow a greenhouse garden.