How to Start Seeds Indoors and Which are Best

I totally understand the intimidation of starting to grow from seed as opposed to buying transplants. But trust me, if you get set up right, you will probably find it easier to garden this way!

Which Seeds are Best to Start Indoors

First things first, make sure the seeds you want to start like being started indoors.

Start Indoors

Most of the Solanaceae, or Nightshade family is best to be started by seed inside except for potatoes. These are the plants that will do well in this family:

  • tomatoes
  • tomatillos
  • peppers
  • eggplant

Additionally, most of the Brassica family does well from being started inside. Radish and turnips are exceptions in this family. Root crops do best started in the ground where they will remain for their entire life cycle. Here are the Brassica that like to be started inside:

  • broccoli
  • cauliflower
  • kale
  • cabbage
  • boc choy
  • mustard greens

Tomatillos and Zinnias

Start Outdoors

Typically, you want to start all root crops outside. Here are a few examples.

  • carrots
  • beets
  • radish
  • turnip
  • parsnip
  • onion

It is also NOT recommended to start Chenopodiaceae plants inside.

  • spinach
  • Swiss chard
  • beets (*also not recommended because it’s a root crop)

Additionally, seed packets usually do not recommend planting Cucurbits inside.

  • pumpkin
  • squash
  • melons
  • cucumber

Lastly, peas and beans are recommended to start outdoors when they will remain for their full life cycle.

Exceptions

There are always exceptions, aren’t there? I have actually had more success starting Swiss chard and cucurbits (specifically pumpkin, melons and squash) inside though it’s never recommended on seed packets.

Take your plant hardiness zone and overall climate into consideration here. In the south, we experience days that are just too hot to start cool season crops outside for fall planting. Whereas in the north, you might not experience enough warm growing days outside for the long season plants. If you have any doubts, ask your local garden store.

Gear for Starting Seeds Indoors

Making your seed starting setup is pretty straightforward and you can get started for under $100. Considering that most single transplants cost $2-$3, around the same cost as a pack of seeds that could include 20 or 30 seeds, growing your own transplants can be a great investment over time. Here’s the gear that I use:

Light

The most economical way to start would be using a super sunny window in your house. This could be tricky depending on your space – you would need full sun for at least 8 hours, if possible. If this isn’t an option, the easiest way to get started, in my opinion, is to buy an LED shop light. It costs a little more than a fluorescent light, but it’s more efficient and puts out less heat, so the operating cost is lower and we don’t have to worry about plants growing too close to the light and burning. Also, it should last long enough that it may be the only one you ever need. At 3,800 lumens, it produces plenty of light to grow a healthy plant until it’s time to plant it outside.

That said, a fluorescent shop light you get for free or cheap will work great, too!

Timer

For convenience purposes, we use a timer like this one. This allows the light to be turned on for longer because it turns on before we wake up. Also, we just don’t have to worry about it. Ours is set to be on for 16 hours per day, from 5am to 9pm in the summer and 5am to 8pm in the winter. It’s probably a good idea to have your lights on during normal daylight hours for your area so that your plants start to get used to that rhythm.

Shelf

I use this shelving system because we got it free from a family member. It is expensive but works really great, which is why I’m still recommending it. The shelves stack so you can remove what you don’t need. I like that the shop light hangs easily from it, I can hang drying herbs and flowers and spray bottles from it and the metal makes it easy to clean if water spills.

Planting Growing Indoors Under Grow Lights

Trays and Planting Containers

I ask for plastic planters from garden stores near the end of spring and fall and save any containers from transplants I purchase. Typically, stores give these to you for free when they have lots laying around after the busy seasons of spring and fall. I bought larger trays to hold the individual containers on Amazon. I wash them with soap and water between each use. So far, they are holding up nicely.

Seed Starting Medium and Seeds

If you are starting small (home-scale as opposed to farm-scale), I would recommend buying a seed starting mix as opposed to making your own because of the quantity you will most likely need when you start. The bags can seem expensive compared to other bagged soil but they go a long way and make a HUGE difference. I ask for gift cards to a local garden store for Christmas and then use them to buy all of our seed starting mix for the year to make it more economical for us. Here’s the mix we use.

Seedlings Sprouting Inside

Spray Bottle

I recommend purchasing a spray bottle to water your seeds before they sprout. It allows you to mist them and helps prevent overwatering.

What to Do After You Plant Your Seeds Indoors

Watering

You want the soil to remain moist but never have pools of water. Check in the morning and at night to be sure the soil is still moist. After your seedlings sprout, it’s best to water by filling up the tray with about ⅛ inch of water as opposed to spraying the plants since their stems are still very fragile. After you fill the tray with water, the water will wick up to the roots as it gets absorbed by the seed starter mix, and the roots will drink up what they need. This is another reason to use a quality seed starter mix. Check the moisture level with your finger to determine how often to water and try your best to be consistent.

Feeding

When your seeds first sprout they will have cotyledons which are part of the seed. These provide the plant with food at first. Then, the plant will get it’s first “true leaves” which look like the parent plant. The cotyledons usually fall off afterwards (don’t be alarmed or think your plant is dying – it’s part of the process) because the “true leaves” take over and begin photosynthesis. This is when you will want to start feeding your plants. I use and highly recommend Neptune’s Harvest Organic Fish Emulsion. I mix it with water as the directions say and then pour it into the seed tray for the plants to drink up. After about a day, I usually take the tray outside and clean it because it may start to smell.

When to Move Outside

There are a few telling signs that will indicate to you it’s time to move the plants outside. For the most part, you will probably be able to tell that it is time based on their size. Here are a few other factors to consider when determining the best timing.

Before You Move Them Outside – Hardening Off

Once your seedlings are ready to be transplanted outside, make sure you harden them off first. Here is a great article that walks you through it.

Mustard Greens Transplanted Outside in the Garden

Conclusion

In order to grow inside, you need to be sure the seeds you want to grow will benefit from being grown indoors and you need the right gear to get them off on the right foot.

Growing from seed inside has allowed me to grow far more food year-round, especially with the harsh summers I experience. My hope is that information has encouraged you to grow from seed and increase your yields as well.

11 thoughts on “How to Start Seeds Indoors and Which are Best”

  1. Thank you so much for the informative article. I am in the process of setting up a 6 x 12 x 7 indoor greenhouse at the elementary school where I work. We have an outdoor community garden where I plan on moving seedlings once they are started. Do you still recommend shop lights for something like this? Also, are there any plants that we should start this time of year?

    1. You are so welcome, Amanda! I’m glad you found it to be helpful! Sounds like you are working on a very exciting project. The greenhouse shouldn’t need any lights! The sun should shine right through allowing enough light and heat. As far as what to plant, it depends on your location. Head over to my article on When to Plant Seeds to determine this for your area: https://www.nourishingpursuits.com/garden/when-to-plant-your-seeds/ . Also, you can join our Beginner Gardeners Facebook group for any future questions! Happy gardening!

  2. Great article. I love gardening and some of the info on when to plant and what to plant is great. For plant containers, have you ever tried using eggshells? When you crack the egg, try to only make a little hole at the top. Put some soil in, plant your seed and voila. When it’s ready to be transplanted just break up the shell a little at the bottom and put it all into the earth. It also provides some nourishment. Hope this is helpful. Thanks again for the great article.

    1. Thanks, Jonathan! I hope you found it helpful! Thanks for sharing the eggshell tip! 🙂 I typically let my seedlings get larger than the space provided in an eggshell before planting them outside, but maybe I’ll try this sometime and see how it goes!

  3. Another bonus to starting your own seeds is you have a much greater variety available than the 4-5 tomato varieties that your local stores sell.

  4. Yes, this is a late comment. I take empty toilet paper rolls, cut an “X” in the bottom, fold them like a box you’d use for storage and fill them with starter soil. After the seed is growing you can plant the entire roll. If you want you can open the bottom up before planting but they decompose pretty easily. It also serves as a collar around the seedling to ward off bugs.

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