How to Start Seeds Inside

Learn how to start seeds inside. These tips will help you have the most success possible while starting seeds indoors. Along with pictures of my own seed starting setup for inspiration, this information will help you gain confidence in growing your own plants from tiny little seeds.

How to Start Seeds Inside

How to Start Seeds Inside (the right way!)

12 years ago, I was an eager and naive gardening gal, fresh out of college and ready to grow her own food…and I bought an expensive seed starting system from the store and put it in….my cold, dark, damp basement (in Wisconsin, during the cold winter months), and then I waited excitedly for my seeds to grow…and they all failed.

That year and a few years after that, I believed that starting seeds indoors was a difficult and challenging thing that only “expert gardeners” could do correctly. But I have always been stubborn, and through the years, I kept researching and experimenting on seed starting and then, somehow, I got to a point in my life where starting seeds inside was very easy.

I don’t know how it happened, but I somehow went from someone who thought that starting seeds was impossible to someone who thought it was super easy. 

Recently, I have had multiple people ask me loads of questions about how to start seeds inside. It made me realize that I’ve been carrying around all of these seed starting tips in my head and I haven’t been sharing them with people who might be struggling like I did not that long ago in my life. My humblest apologies. Allow me to fix that right now.

NOTE: Make sure you check out my article on Common Seed Starting Problems and Solutions for more information on seed starting issues!

How to Start Seeds Inside:

1. Buy Good Quality Seeds

Those seed packets on display at generic stores are often old seeds. Plus, they are left in the direct light all day long and often in warm temperatures. Good quality seed companies understand that seeds stay fresh and viable longer in dark, cool places. In addition, most stores will carry only generic varieties of vegetables, and those might not be the best varieties for your garden zone. Click here to read more about how to find the best High Quality Seed Companies. That article will also give you a list of good seed companies that you can check out.

How to Start Seeds Inside: Seeds
Purchasing good quality seeds AND checking the viability of my old seeds.

2. Check Your Old Seeds for Viability

Don’t just throw away the seeds from last year that you didn’t grow! Use this simple test to check your old seeds for viability. I keep my seeds in a back corner of my refrigerator and it keeps my old seeds viable for many years. There’s no point wasting time and energy trying to get old non-viable seeds to grow, so doing this simple test will give you a boost of confidence in your seed starting for the year.

3. Presoak Seeds

Not ALL seeds need to be presoaked. If you get seeds from a good quality seed company, you will probably find additional information about each specific plant you are growing on the back of the seed packet. Typically, the bigger the seed, the more likely you need to presoak the seeds before seed starting. 

Presoaking helps to break the seed’s dormancy and can reduce the germination time by several days. After you have checked to see if the specific seeds benefit from presoaking, simply place the seeds in a bowl with room temperature filtered water. Let them soak overnight, then strain and plant in your preferred seed starting dirt/containers (see #4 below for more on that).

Make sure you put a label on the bowls if you’re presoaking multiple plants at the same time! Otherwise, you might be guessing which plant is which….trust me… (I’ve done this many times).

How to Start Seeds Inside: Peat Pellets4. Decide on Your Growing Containers 

There are MANY different container options for starting seeds indoors. I have tried a lot of them.

Here are the most popular options and how they worked for me:

  • Plastic Seed Starting Containers: I personally hate these. You either need to buy new ones each year or VERY CAREFULLY pop your seedlings out of the containers when transplanting them outside. It’s super time-consuming to try to reuse the containers, and I hate the idea of using this much plastic. You might be able to find some for free/cheap from a local gardening store, however, so if they work for you, go ahead and use them.
  • Reusing Toilet Paper Rolls: I did not like using these. It was difficult not to have them fall apart before transplanting them and the cardboard can get quite fragile when watering them. It was also too constricting for the roots of seedlings that need to be transplanted to bigger pots at some point during the indoor stage (like tomatoes or peppers).
  • Recycled Containers (with drainage holes poked in bottom): Yogurt cups, sour cream containers, etc., can be used for starting seeds indoors. My main gripe is again, getting the plants OUT of the containers without harming them when transplanting to the garden.
  • Soil Block Maker: You can compress soil into a cube when starting seeds indoors. I have NOT used this, and my only concern is preventing them from crumbling apart. If you have used this method and you prefer it, please let me know!
  • Peat Pots: I hate that they can be expensive and that they can only be used once, however, I LOVE that you simply tear the bottom off and plant the seedlings in the peat pots right into your garden. It makes it super easy. These peat pots are great for starting seeds. I use these peat pots for my tomato and pepper seedlings when they need their first transplant while they are still indoors.
  • Peat Pellets: This is my favorite growing method for when I start seeds inside. You can get a HUGE bag of peat pellets for a decent price. They are small, so you can grow many plants at a time in the same tray. You can get this awesome peat pellet kit, which comes with the tray, top, and some peat pellets, and then after that, you just need the extra peat pellets. It’s WAY less messy than using soil inside and the roots grow right through the mesh, so you don’t have as many root problems during transplanting.

If you don’t use peat pellets when you start seeds inside, you will also need to get a seed starting soil mix. Do NOT use soil from your garden or compost pile or re-use potting soil from your houseplants. These soils can introduce disease to your vulnerable seedlings. Seed starting soil is specifically made to ensure healthy seedlings.

If you are wincing at the price of seed starting soil mixes, you can try to make your own. Here’s a great DIY seed starting soil recipe that I’ve found. I usually only buy ONE bag of seed starting soil each year and I only use it for my tomato and pepper seedlings. Peat pellets are WAY more budget-friendly for me. 

Pre-moisten the seed starting mix before you fill your chosen containers. I usually fill a bowl with some of the soil mix and put it in my kitchen sink and I add just enough water to make the soil slightly hold form when I squeeze it in my hand. Once properly damp, scoop the seed starting mix into the containers and gently press it down to remove any air pockets. 

NOTE: You could also look into something like compressed coconut coir. I have not done any research on this type of soil yet, but I know it’s pretty popular.

5. Heat

Whenever I have a friend ask me for help when they have problems after they start seeds inside, the first thing I always ask is: “Do you have a seed heating mat?” They almost always answer “No” and that’s usually why there is a struggle for them. 

Most garden seeds need soil temperatures of around 65-75 degrees Fehreinheit in order to germinate and be healthy. Most of us will struggle to get our homes in the winter to stay at those temperatures for the seeds. Even if your air temperature is around 65 degrees, the SOIL needs to be that temperature, which is easier to achieve if the heat comes from the bottom of the seed containers/trays. 

You can try placing the seed trays on top of your refrigerator or near another heat source in your home. However, if you want real success with starting seeds inside, you should get a seed heating mat. Here’s a decent priced and reviewed heating mat if you want a budget-friendly heating mat. 

How to Start Seeds Inside: Heating Mat6. Humidity

When you first start your seeds, AKA after you put seeds on your preferred soil in a container or in a peat pellet, you need to cover the containers/trays in order to help give the seeds some humidity. This is why I start with the peat pellet kit, so it comes with a tray and a perfect fitting top. I simply put the top mostly on, so it traps the moisture in the air. 

If you are using another type of container, simply use a plastic wrap or something else to mainly cover the containers in order to trap humidity.

Once most of the seeds sprout on that tray, remove the top. You only need the humidity to help make the seeds sprout. After that, the humidity can actually cause problems like damping off or fungus.

How to Start Seeds Inside: Lighting System
My Seed Starting System: Lighting Setup

7. Light

When friends ask for seed starting help, after I ask about the heat, I then ask about the lighting. I hate be the bearer of bad news, but you will usually have only limited success if you try to use just the light from your window to start seeds. Seedlings need at least 12-16 hours of light each day. 

It’s best to have a tube or two of either full spectrum fluorescent or LED light bulbs shining just a few inches above your seedlings.

You do NOT have to buy one of those fancy (and expensive) seed starting lights online or at the store. You can very easily make your own. I made my own lighting system with the cheapest possible lighting fixtures that I purchased from a local hardware store. If you would like some DIY inspiration for a seed starting light fixture, check out Brown Thumb Mama’s seed starting light or The Prairie Homestead’s light system. These are both great setups and they are both different from each other, so you can be inspired to use different supplies, depending on what you want to use.

Whether you make your own light system or buy one, just make sure the lighting is adjustable. As the seedlings grow, you will need to adjust the position of the light fixture so that it remains 2-3 inches above the plants.

For my seed starting light setup (see photo above), my bottom row lights are NOT adjustable, so I have to raise and lower the plants manually with blocks and containers, which does get a bit tedious. This was the best way I could figure out how to have a double layer setup though, so I just live with the minor annoyance.

Tip: If you want to save time/hassle, consider getting one of these awesome automatic timers. I have my lights automatically set up to turn off and on, so I don’t have to constantly think about it. It is a major stress-reducer!

How to Start Seeds Inside: Automatic Timer
My automatic timer makes seed starting SO much easier!

8. Proper moisture

For the first week or so after you start your seeds, your seedlings won’t need much water. This is especially true if you use peat pellets, which you soak thoroughly before sowing the seeds.

From then on, it’s a delicate balance between too much water and not enough. If you use heat mats, your plants will get dry faster, so you might find that you need to water them more often. You don’t want to overwater seedlings because this can cause damping off and other fungus and mold issues. However, you also do not want to wait until the seedlings are wilting from lack of water. 

The key is to keep the soil moist but not soggy. Some people prefer using a mister or spray bottle to maintain this balance, and others use things like turkey basters or small watering cans. I personally prefer to water my plants from below.

This is another reason why I love peat pellets and peat pots: I pour a small amount of water in the tray and allow the peat pellets and peat pots to soak up the water from the bottom. This helps me avoid most fungus/mold issues and my plants get the moisture they need. 

Figuring out the perfect balance of moisture for your seedlings is something that takes practice. If you are worried about it and/or you are a beginner, I highly recommend starting with peat pellets and giving them water from the bottom. Once you’ve figured out what plants and soil look like when they need more or less water, you can then graduate to your preferred containers.

Additional Tips for How to Start Seeds Inside:

**Automatic Timer: I highly recommend using an automatic timer for your lights so that you don’t have to constantly remember to turn the lights on in the morning and then turn them off at night.

**Fan: If you struggle with fungus, damping off, etc., you might want to get a fan to blow on your seedlings to help prevent the air from getting too humid. The fan can also help get your seedlings prepared for windy days when they are finally transplanted outdoors. I do not use a fan, but I know many people who use them.

**Fertilizing:  Most seed starting mixes do not contain nutrients. When the seeds produce their first True Leaves, you might want to consider a light feeding for them. Make sure you use an organic liquid fertilizer, my favorite is liquid fish emulsion, and dilute it to at least half-strength (consider starting even weaker than that). WARNING: this will make your house smell bad. I personally do not fertilize my indoor seedlings unless they are showing a nutrition imbalance (leaves are discolored or falling off).

**Thin plants until healthiest one remains: I HATE thinning plants. However, some seeds are so small that you can’t help but sow a thick amount of them in one tiny container (I’m looking at you, chamomile!). Ideally, you only want one seedling per container, so you should thin the plants to end up with the strongest and healthiest one. You want to do this early on in order to avoid root disturbance to your chosen healthy plant. If you can worried about root disturbance, simply snip the unwanted seedlings at the soil line.

**Transplant to larger containers: Some seedlings will outgrow their chosen containers before it is time to transplant them outdoors. I find this especially true with peppers and tomatoes. Once their roots are coming out of the peat pellet mesh, I know it’s time to transplant them to larger containers. I usually transplant mine to peat pots with seed starting mix. As long as you choose a container that is larger and you continue to use seed starting mix, use whatever container you want. Many people like to use 16 oz. plastic drinking cups if you need an idea.

**Properly transplant outdoors: There is nothing worse than going through all the work of properly starting seeds indoors only to watch them die the moment you move them outdoors. It is very important that you properly harden them before transplanting them outside. You need PATIENCE for this step. A few weeks before you are going to transplant them to the garden, begin adjusting your seedlings to outdoor conditions. Start with just a few minutes outside on a warm sunny day and work your way up, until the plant has grown used to wind, rain, sun, cool nights, etc.

How to Start Seeds Inside: Seed Starting Setup
I’m ready to start seeds for the year!

Finishing my Seed Starting Tips with Budgeting Advice…

I have a super strict gardening budget. My obsession with careful garden budgeting started when my hubby and I were super poor and living in a rv in order to save money. Even though we are doing fine financially now, I still follow a strict gardening budget because my love for gardening can get out of hand if I don’t keep a careful eye on the budget.

So I totally understand if you’re adding up the cost for the lights, heating mat, automatic timer, peat pellets, trays, etc. and you’re freaking out about the price. My best gardening budget tip: start slow! Also, start with only the necessities. 

I started with one light, one heating mat, one tray, homemade seed starting soil, and recycled pots. Every year, I only add extra seed starting materials if I have some spare money in my gardening budget.  Sure, having all the things I have now really help with my germination and seed starting success.

However, my main joy in gardening is learning how to grow things. Starting slow can help you develop a good eye for gardening details. For example, starting with only 25 plants because of a budget just means that those 25 plants will get more of your love and attention. 

I hope you find joy and success as you begin starting seeds indoors! I also hope my advice here helped you learn how to start seeds inside. Read more about Common Seed Starting Problems and Solutions in this article.

Please tell me about your seed starting adventures in the comments below! I love hearing from you!

More Spring Gardening Tips:

How to Properly Start Seeds Inside

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  1. I have a grow light that I got at a yard sale cheap, is that a good choice for seed starters? Also, are clip on shop lights too hot for starting?
    I’ve never started seeds before but we have recently bought 11 acres and live in a small trailer to save up to build a house. I have a 9X12 shed that we have converted to a laundry room now, and we have built shelving for pantry storage and sewing room. I have shelving space dedicated to try starting seeds. Any additional advice would be appreciated.

    1. A grow light is perfect for seed starting! Shop lights might be too hot. I hope you have a great season!

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