Here’s an easy tutorial for how to start plants from seeds to save money and have the varieties you want – and when you want – to plant them in your garden. It’s the best thing you can do for your garden!
You can find even more seed starting information in our Seed Starting Guide.
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Let’s start some seeds! In this second installment of the Vegetable Garden 101 series I’m going to share how to start plants from seeds indoors, weeks or months before your planting season.
This way you can use your own seedlings when it’s time to plant in your area, saving money and by-passing the stores. Even more importantly, they will be available when you are ready to plant on your timetable.
Is this tutorial only for vegetable seeds?
Even though this is part of a vegetable gardening series, the basic steps outlined here to grow plants from seeds work for any seeds, whether they are vegetables or flowers. In fact, I often grow flower seedlings right along with my vegetables.
My favorite flowers to grow indoors from seed include:
- zinnias (they get a head start on blooming when planted early indoors)
Whether you’re growing vegetables or flowers, it’s so rewarding to see those first sprouts, knowing they will become the food your family will be eating in a few months, or blooms gracing your table.
Why should I start plants from seed?
I explained this more fully in this article about the “big four” reasons why it’s a great idea, but here is a brief recap:
- To save money. Most seeds are viable for 3-5 years, so that $2 packet of seeds can provide plants for a number of seasons, though you’ll want to be careful buying supplies.
- For control and selection. Probably the biggest reason I start plants from seeds is to choose new varieties to try without being at the whim of a nursery buyer.
- To have the best growing dates for your garden. You can time your seedlings for your specific frost dates, stagger dates, as well as plant a fall garden when it’s nearly impossible to find starts in the stores.
- It’s fun!
It’s not hard to start seeds, but it always helps to have pictures, so I’m sharing this tutorial on how to start plants from seeds step by step using the simple technique that I’ve used for years.
How to Start Plants From Seeds
Basic Supplies To Start Seeds
- Seeds. Buying from online catalogs will give you the best selection and quality, but there’s nothing wrong with buying from the store, as long as it’s from a quality seed brand. Another benefit of catalogs: there’s a TON of growing information in them, so you can learn a lot, too. Go here to see a list of catalogs I like to buy from.
- Grow light or a basic shop light with 2 fluorescent lights, one warm & one cool. I’ve always used the basic shop light set up at about half the price of ‘official’ grow lights and it’s worked great. Make sure they have chains or ropes so you can raise and lower to lights to be right over the seedlings as they grow.
- Plastic planting tray unit with a clear dome and twelve 6-cell pots which last a number of years. I find planting in cells much easier than just laying the seeds in flat trays filled with soil – there’s less thinning needed and less root disturbance when planting. You can buy the trays without the 6-cell pots, too, and fill them with reused 4-inch nursery pots (18 fit perfectly) to fill them (you can see this pictured above in the back left tray). The larger pots are great for peppers and tomatoes which need to grow pretty big before being planted – it means one less transplant to do.
TIP: To reused plastic pots and cells, wash them out yearly with a good spray of water. Some say to use bleach, but I don’t like using it and have never had a problem with fungus issues since I use sterilized potting soil.
Note: I don’t recommend the “Jiffy Pots” type of trays or pots you may see in stores – they dry out faster and actually stunted the growth of some of my plants when I planted them directly into the garden as instructed. The roots weren’t able to grow through the membrane and became root-bound.
- Sterilized seed starting potting mix. This is usually a soil-less mix that’s made especially for starting seeds. I’ve never skimped by trying to reuse old soil since that’s one of the ways to introduce a fungus to your seedlings. A quality seed starting mix is the basis of great seedlings, so it’s worth the (slight) extra cost. Some potting mixes even include extra nutrients or fertilizers (though I recommend organic) to give your seeds a boost.
- Plastic garden labels – this link is to my favorite labels- not too big so they fit in the trays, easy to read, and last a number of years.
- Sharpie or garden marker pen. Every time I think I will save time by not labeling every single plant cell, I am sorry. You will want to know what you loved so that you will be sure to grow it again AND you will want to know what not to plant again!
- Old mixing bowl or container for wetting soil.
- Large spoon or soil scoop for mixing and filling cells.
- Chopstick or small tool for making shallow indentations, plus small spoon for planting small seeds.
How to Plant Seeds Indoors
1. Gather seeds to plant.
Read the backs of the seed packets to find when to start indoors according to your last frost date and when you want to plant out in your garden (it may be different if you are using covers in the garden and you can plant earlier – again, another great reason to start your own seeds).
Plan how many of each seed variety you want and have room for. (HUGE TIP: start small – you probably don’t want 12 heads of broccoli all at once…)
TIP: How to Store Seeds
Pictured above is my simple and basic seed-saving system: a portable file box (which should be opaque so light doesn’t get through) with a lid and hanging files with alphabet labels.
I put individual seed packets in baggies according to type (i.e., all broccoli varieties together in one baggie). The baggies make it easy to find the packets when I want to plant carrots or whatever, and they are supposed to help keep the packets better for storage.
Then the baggies are filed alphabetically. I keep this file box in a cool but heated area (our laundry room). It works great – I have used 5 year old seed from this system and had them sprout fairly well.
2. Wet the seed mix.
If you put it directly in the cells and then try to wet it, the centers will still be dry and you’ll have to stir each individual pot, which is not easy. I have learned this the hard way – always wet the seed mix first.
I use an enamel pot, fill it with starting mix, and add water. It takes awhile to get it thoroughly mixed, depending on the amount of peat that’s in your mixture. Which is why some people add the mix dry to the cells – it’s easier to spread. But don’t do that – trust me on this, okay?
3. Push the wet mix into the potting tray cells, tamping down to firm.
The soil will probably be somewhat clumpy, and may not go into the cells nicely for you, so don’t be afraid to get dirty!
Fill the cells/pots full, because when you water them the dirt will sink a bit and you want as much soil as possible for your little seedlings.
4. Make labels and place in trays.
Use the sharpie/garden marker to write what seed variety will be in the cell on a plastic label and place them in the trays where you’ll want the seeds to go before planting.
Doing this first helps map out your placement, determine the amount of room you have AND helps avoid the mystery plant syndrome.
5. Use a chopstick or other small tool to make a shallow indentation, then sprinkle in 2 or 3 seeds.
You’ll eventually thin to 1, but this allows for different rates of germination. Flat, bigger seeds are easy to add to the indentations with your fingers, but for those tiny seeds like onion and broccoli, a small spoon makes it easy to add only a couple.
TIP: plant more than 2-3 seeds if using older seed packets because the germination rate goes down as it ages. Yes, it means there may be more thinning involved which seems wasteful, but believe me, it’s no fun to do all this and have only two seeds germinate in a 6-cell and then have to do it all again, only this time much later!
6. Gently cover the seed.
Most of the seeds we start inside are not big ones that need to be deep in the soil, so just barely cover the seed. You can use a bit more of the dry mix or push some of the moist soil back over the seed.
TIP: I wait until I’ve added all the seeds to the tray before covering them, just to make sure I fill all the cells.
7. Plant all cells and water with a gentle WARM spray.
The warmth will give the seeds a little head start, but the real key is to gently water. You can use a sink faucet spray on low or fill a watering can to water with. Be careful not to flood the cells too much as that will displace the seeds.
8. Place a cover over the tray.
You don’t technically have to use a cover, but it does help retain moisture until the seeds sprout. If you use one (I always do), you will need to remove it as soon as you see some sprouts, even if there are not some in every the cell. The extra moisture that was great for germination can cause fungus problems on the newly germinated seedlings.
9. Set the tray under your grow light.
BUT don’t turn them on yet – the seeds don’t need light at this point (while there are a few seeds that need light to germinate, it’s mostly flowers that do – check the seed package).
10. Turn on the lights when there are sprouts. Adjust the light fixture as close to the tops of the sprouts as possible. This close light is key to stocky, healthy seedlings. Move the light fixture up as the seedlings grow.
11. Keep moist by watering from the bottom. Always add water to the plastic tray (another reason I like using the cells) – lift a pot/cell and fill tray with water to keep the cells all evenly moist.
What about fertilizer?
If the seed mix you used has some included, you won’t need to add any for most plants grown for 4 to 6 weeks indoors. For longer growing plants like tomatoes and peppers, I often add a diluted fish emulsion to the water at the halfway mark.
Where to Grow Your Plants Indoors
One of the questions I get asked the most about how to start plants from seeds is:
“Where can I grow trays of seedlings, and how do they get light when they’ve germinated?”
Windows or Lights?
The most basic source of light is windows, of course, but it’s usually not strong enough to produce strong, stocky seedlings. The seedlings will strain towards the light, growing tall and leggy, especially if you’re growing a large tray like I show.
That’s why I suggest a light source that can be placed directly over the pots like the options listed in the supplies section.
The light can be attached to a shelf or under a cabinet or you can build a simple stand to hold the light. You just need to have the ability to raise and lower the light source as the plants grow.
Ideas for Where to Start Your Seeds Indoors
As for where to grow them – wherever you can make a bit of space for a few months!
In the Kitchen: For many years, my answer to that was a corner of my kitchen, shown above. The shop light was hidden most of the year and when I needed the light, I moved the storage jars, set my trays in place and lowered the light for the few months I’d need.
Use a Structure: In a previous house we built a simple structure out of 2x4s that we hung the lights from and kept in an office. Wherever you keep the light though, it should still be in the house, or at least someplace where it doesn’t get too cold.
Under a Shelf: I now have a dedicated seed starting area I planned for our mudroom, seen above. I love not having to move items out of the way when I want to grow some seeds!
Wondering how to germinate seeds quickly?
Use a heat mat! This is especially helpful if your house is always on the cool side. I was able to find a heated grow mat for a good price and found it really does help seeds to sprout sooner, especially vegetables like peppers. I love it! Click Here to see the mat I use.
Next up in the Seed Starting Series:
Note: AOC’s classic vegetable gardening series was published in the first year of the blog – 2009. It’s been republished with updated information and clearer formatting.
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