Do you want to learn how to start seeds indoors? A lot of people give it a shot because buying seeds is a lot cheaper than buying seedlings. However, starting seeds can be a tricky proposition that sometimes ends up costing more money than we thought it would.

If you’d like to try to start your own vegetable and flower seeds indoors, here’s what you have to know: what supplies to have on hand, tips for best success, and mistakes to avoid.

For getting the timing right, read when to start seeds indoors.

How to Start Seeds Indoors to Save Sanity, Time, & Money

Seed Starting Supplies

Starting seeds correctly can require a lot of supplies which means it can be quite expensive. Here are a few supplies we think you’ll need to have the best success. Look for used supplies if you’re on a budget. Lots of people decide starting seeds on their own is not worth the hassle!

• Seeds – You’ll need high quality seeds for best success. If you’re looking for more, these are my favorite places to order garden seeds.
• Containers – You can use lots of household items or reuse seed starting containers from previous years. However, make sure you clean them well before reusing.
• Heating pad or warming mats – (Useful for helping the seeds to germinate.) I use warming mats because it’s a little cooler in the basement where I start my seeds. Some seeds need warm temperatures for a quicker or higher germination rate so these mats can be quite helpful. If you don’t have any supplies, this seed starting kit with warming mat seems to be a pretty good value.
• Grow light – (I use T-8 Grow Fluorescent bulbs like these.) You’ll need fluorescent lights for most seedlings. Even if you put your seed tray in a south facing window, the seedlings won’t get enough light. Lack of light is why seeds started indoors often get leggy.
• Organic Seed Starting Soil – You can buy organic potting mixes from your local garden center or hardware store, or order on Amazon and have it shipped directly to your home. You can also easily make your own. Soil’s obviously a pretty important component to starting seeds so sometime’s a ready-made mix is not the best choice. Find a good soil that’s too heavy and not full of synthetic ingredients.
• Coco coir pellets – If you want a soilless seed starting medium, use coir pellets. I’ve used them and they work well initially, but you will need seed starting mix at transplant time.
• Light Timer – Very handy for making those lights turn on and off on their own. Despite my best intentions, I forget every single night to turn off the lights. Having this handy little supply makes sure my seedlings have both light and dark – important for their proper growth.
• Garden Plant Labels or Popsicle sticks – It’s very important to properly label your seeds. Let me just tell you, all the varieties of tomatoes look the same after they sprout. Label your plants if you don’t want to end up with 25 cherry tomato plants and very few canners like I did a couple years ago! 😀
• Organic fertilizer – we have had great success with seedlings using Fox Farm liquid fertilizer earthworm castings, Norwegian kelp meal, and essential micronutrients. It doesn’t take a lot, but it does make a big difference.
• Shelf – I’ve stored my seeds on a lot of different types of shelves (homemade and store-bought), in window sills, on tables – whatever I could find. It doesn’t really matter what you set your seeds on, but some types of shelves will be easier than others, especially if you use grow-lights. But I do have to say, I really love my heavy duty metal shelf on wheels. It’s perfect for seed starting!
• Cinnamon for sprinkling on seedlings after germination to help prevent fungal disease and fungus gnats.

One thing you DO NOT NEED is peat moss. Coconut coir fiber is a more environmentally friendly option for seed-starting mixes as it comes from a renewable resource. It’s a leftover by-product from coconuts used for food so using coco coir helps keep materials out of landfills. It also has a neutral ph level which is better for delicate seedlings.

Canadian sphagnum peat moss comes from peat bogs which are essentially strip mines. They’re not good for the environment. Additionally, peat moss is often more acidic than garden plants like. Read more about peat moss vs coco coir here.

Best Organic Seed Starting Mix

It’s very easy to make your own seed starting mix that you’ll find to be superior to store bought mixes. A lot of the garden soil seed mix you can buy at garden centers is too heavy for young seedlings. Soil compaction can become a problem as can water retention.

Luckily, it only takes four natural ingredients to make your own organic seed starting mix that’s full of healthy organic material! And, it will give seedings the best chance to grow into healthy plants for your vegetable garden! The best part: it’s cheaper to make your own mix! Here’s how to make your own best organic seed starting mix!

• All purpose potting soil – choose a growing medium that doesn’t have synthetic fertilizers
• Perlite – nice and lightweight, it doesn’t break down, helps the soil have good drainage. That means helps your seedlings have room to grow deep roots
• Compost – for adding extra nutrition for your seedlings. Make sure that it is well-aged compost and very fine, so run it through a sieve need be.
• Worm Castings – a key ingredient in your homemade soil starter – it’s full of nutrients and minerals that will be easily absorbed and help make stronger seedlings.

Simply mix equal parts of these four ingredients. Using a 5 gallon bucket with a gamma lid works well. Before you add the mix to your free starter pots for seeds, make sure to wet it down well. 🙂

Learn how to get started worm composting to make your own worm castings!

Free Starter Pots for Seeds

You don’t have to buy expensive containers to start flower or vegetable seeds – a lot of items you already have around the house will work quite well for indoor seed starting! Here are a few items to save from the trash which make (and free!) great starter pots for seeds!

I love these ideas because this stuff is either trash, compost, or recyclables. It’s much better to re-use things, in my opinion! And some of these seed starting containers can be planted directly in the ground to decompose around my plants. They were easy to find in my house…and easy to prepare and plant, too!

Using Egg Cartons to Start Seeds

Do you have piles of egg cartons? Use them for seed starting! You can use plastic egg cartons or even better, cardboard egg cartons for seed starting. To use egg cartons for seeds, poke drainage holes in the bottom of each egg area, fill will potting mix, and plant. 

You’ll want to put the egg cartons on a tray to keep excess water from spilling all over your seed starting shelf. While you can use any type of egg carton, cardboard egg cartons are biodegradable and can be planted right in the soil or added to your compost piles.

Note: If you use egg cartons or egg shells, you will almost certainly need to pot-up your seedlings in larger containers. There won’t be enough room to grow strong roots.

Using Egg Shells to Start Seeds

To use egg shells, simply rinse and fill. Easy peasy! The most difficult part is making to break your eggs nicely to end up with a little pot.

Toilet Paper Rolls Make Great Starter Pots for Seeds

There are a couple ways to use toilet paper rolls as seed starter pots. You can cut the toilet paper rolls in half and put them in a plastic shoe box.

Or, you can cut the bottom of the roll and fold it over to make a bottom. You do what makes you feel more comfortable. I skip the bottom and it works just fine – but I don’t move the seedlings around much after putting them inside the plastic shoe box.

Other Plastic Containers

Many plastic pots make great starter pots for seeds including: 

• Takeout containers
• Solo cups
• Yogurt containers
• Leftover lettuce boxes
• Any leftover pots from past garden plants

Just make sure to wash containers thoroughly before using and poke drainage holes in the bottom of each container!

How To Start Seeds Indoors – an easy technique

Starting the seeds and getting that first set of true leaves is pretty easy, you guys. The hard part is keeping that seedling alive and growing it into a healthy full-grown plant.

Here’s what to do in a nutshell:

First, read the back of the seed packet. Make sure you know when your last expected frost date is and that you understand when to start your seedlings indoors. In vegetable gardening, a good rule of thumb is to plant most seedlings outside after your danger of frost has past, but some hardy plants (brassicas, greens, and some flowers) can be planted before.

Check your frost dates by zip code at Dave’s Garden.

So your seed starting timeline will vary based on where you live and also the type of seedling you’re growing. You’ll need to start seeds at different times, so make sure to read this post on when to start seeds indoors to get the timing right.

Prepare your pots and seed starter mix per ingredient directions. If you’re using pellets, soak them in warm water to make them expand. You’ll also want to wet any seed starting mix thoroughly before putting it in your pots and adding the seeds.

Then, put one or two seeds in each pot and cover with a small amount of soil. If you’re planting tiny seeds, you may need tweezers or a tiny seed planter tool to help.

Finally, make sure to label the pots somehow, as seedlings often look very similar – especially different varieties of the same type of plant – different types of broccoli or tomatoes for instance. 

Put your pots in a greenhouse and put on a lid. Or, cover the seedlings with plastic to help retain moisture so the seeds germinate. 

Watering Seedlings

Seeds need water to germinate, so you’ll want to make sure that the soil stays very moist as you’re waiting for the seeds to pop up out of the dirt. That’s one reason why we recommend covering your seed starting containers to create a humid, mini-greenhouse environment. 

Once your seedlings germinate, you need to continue to water them often. Seedlings need to be kept consistently moist so you may be watering them a few times a day. Don’t let them dry out. A spray bottle is a great way to keep your baby seedlings watered.

What to do after seedlings germinate

Several factors determine seed germination, so you’ll want to pay attention. In order to germinate properly, you’ll want to only use a high-quality seed. To get the best seed germination rate, pay attention to temperature, moisture, air, and light.

Once the seeds germinate, turn off the heat mat, and turn on the lights. You want your lights to be as close to the seedlings as possible to prevent the seedlings from becoming leggy. As the seedlings grow, you will need to adjust the lights and move them up.

Planting seedlings outside

Once you have strong seedlings that have true leaves, it’s time to consider planting seedlings outside. Before you do that, you’ll need to harden off your seedlings so you don’t shock and kill them by suddenly moving them outside. 

It’s important to watch the weather and pick the best time for planting. Different seedlings will go outside at different times. 

Brassica seedlings can be transplanted into the garden several weeks before the first frost, if the soil is workable and the weather looks good.

Warm weather seedlings like tomatoes, cucumbers, peppers, eggplants need to wait until all danger of frost has passed!

Whenever you plant your seedlings outside, make sure that you harden off your seedlings. Really, I can’t say that often enough!

7 Common Seed Starting Mistakes to Avoid

Starting seeds takes time and dedication. If you think it’s not for you, you will probably be money ahead to buy seedlings. I can’t tell you how many seedlings I have killed by not watering correctly or by not hardening off correctly.

If you decide you definitely want to give seed starting a chance, here are seven mistakes to avoid.

1. Starting seedlings at the wrong time – make sure you follow best practice for when to start your seedlings. If you don’t give them enough time to grow, they won’t be strong enough to transplant. If you start them too early, you run the risk of killing them before you get to plant them.
2. Not providing enough light – make sure your seedlings get enough light. Otherwise, you’ll end up with leggy, weak seedlings that won’t survive the transplant. Even putting young plants near a sunny window is not enough to give them the best start.
3. Not thinning – it can be scary to thin seedings, but you have to in order to get the strongest seedling possible. If you plant to many seeds and they all germinate in one pot, make sure to thin the weaker seedlings. You can eat some seedlings as sprouts, feed them to your chickens, or pot them in a different pot. Just don’t let them all grow in the same pot.
4. Not potting up – make sure that you pot up your seedlings as they grow. They need room, soil, and space to become the strongest seedlings for your garden.
5. Under-watering – to get your seedlings off to a good start, you need to water correctly. Under or over watering will not encourage optimal root growth
6. Not hardening off – harding off is one of the most important steps before you move seedlings to the garden. Make sure you follow best practice for acclimating your delicate plants to the mean, windy outdoors.
7. Not providing warmth – using heat mats is a great idea if you’re having trouble with germination. If your seed starting area is cool, you might have to provide warmth to get your seeds to sprout.

Now that you have the deets, what’s the most challenging part of seed starting for you? Share in the comments!

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