Growing seeds indoors is fun, but it can be tricky and frustrating for beginners. I want to make it easy for everyone.
So, in this post I will give you tons of tips from when to begin, all the way through germination, including how to start seeds indoors, step by step.
There’s no doubt that starting seeds indoors is a great way to get a jump on the gardening season. Plus it’s a great way to save yourself some money.
But it’s not always easy to grow your own seeds, especially inside the house where the conditions are not ideal for them.
Trust me, I know. I struggled for years to get it right, and perfect the art of starting seeds indoors. The good news is that this guide will make it much easier for you!
Below you will learn how to start seeds indoors the right way, so that you have the fastest and best success.
Why Start Seeds Indoors?
The main reason why people start seeds indoors is to get a jump on the gardening season. This is especially true for those of us who live in a cold climate with short summers like I do here in MN.
But there are lots of benefits to planting them indoors vs using other methods to grow seeds. Here’s a list of some of the most important reasons.
- Long-season vegetables and flowers have plenty of time to mature before frost
- You’ll get an earlier and better harvest from your crops
- Germination rates are more consistent in a controlled indoor environment
- Since the seeds are protected, there’s less risk of losing them to pests or harsh weather conditions
What Seeds Can You Grow Indoors?
The good news is that you have tons of options for what types of seeds you can grow indoors. But don’t fall into the trap of thinking that you should start every kind inside.
To figure out which ones will work the best, always read the packet first. That will tell you the recommend method to use.
In general, the ones that should be started indoors are seeds that require warm soil to germinate, those that are slow to sprout, or any that need an extra long hot summer to flower or produce fruit.
Take a look at my list of some of the easiest types to start indoors to get more ideas.
When To Start Seeds Indoors
To figure out when to start seeds indoors, always read the packet. It should tell you the recommended dates for each type.
Generally speaking, you should start planting them indoors six to eight weeks before your average last frost date.
From there, you can make a list of everything thats need to be started around the same time, and begin by planting the ones that will take the longest first.
Getting the timing right is one of the biggest struggles for new gardeners. It may take a little bit of trial and error in the beginning, but don’t worry, you’ll get the hang of it. Learn how to figure out exactly when to start here.
How Long Does It Take To Grow Seeds Indoors?
The amount of time it takes to grow seeds indoors totally depends on what you have. Some are much slower than others.
Again, reading the packet will give you the details. You should be able to find both the expected time for germination, and also the maturity date.
What You Need To Start Seeds Indoors
You don’t have to buy a ton of expensive equipment to start seeds indoors, but you will need a few things.
In this section, I’ll talk about what is required, as well optional items that are nice to have. See my full list of the best seed starting supplies here.
Choose The Right Containers
Using containers that are specifically designed for growing seeds indoors will make it much easier for you. So, if you’re a beginner, I recommend using plastic trays, or buying some kind of a starter kit.
The trays and cells are the perfect size, and the clear lid allows light and moisture in, prevents the soil from drying out too quickly, and helps retain heat.
Use The Best Soil For Seeds
The best type of medium to use for starting seeds indoors is a sterile, lightweight, soilless mix that is both fast draining and also holds moisture.
Whatever you do, don’t cut costs when it comes to the type of soil you buy. Quality is very important here.
Using the wrong type can prevent germination, or cause other problems down the line. The best medium is a commercial mix, or you can use peat pellets instead, if you prefer.
You can also make your own using a mix of coco coir or peat moss, perlite and vermiculite. Learn how to make your own mix here.
Related Post: Peat Pellets Vs. Soil: Which Should You Use And Why?
Provide Adequate Light
While a south facing window is the ideal location for indoor seed starting, it won’t provide strong enough or consistent light.
Not providing adequate lighting is the biggest mistake that newbies make, and one of the main causes of failure. It’s difficult to grow strong, healthy seedlings indoors without using artificial light.
You can buy a light system, or get a fixture with a bulb and hang if from a shelf. Optionally, you could make your own DIY lights for seedlings.
I also recommend getting an inexpensive outlet timer to make it a snap to provide the perfect amount of light for them.
Consider A Heat Mat
Though not required, a heat mat is a really nice thing to have for growing seeds indoors. Adding bottom heat under your trays helps speed up germination, which means they will sprout much faster.
Don’t worry, you don’t need to buy one for every single tray, you can rotate them. Once most of them have germinated in one tray, move the heat mat under a different one.
Planning For Indoor Seed Starting
Before you start planting seeds indoors, you should take some time to prepare. Below are a few of the most important things to do to set yourself up for the best success.
Make A List Of What You Want To Sow
Making a list of the seeds you want to grow indoors is the fun part. My biggest piece of advice here is don’t go too crazy, especially if you’re a beginner.
I recommend only choosing a few of your favorites, rather than trying to do a bunch of them the first time. Otherwise, it’s easy to become overwhelmed.
Read The Seed Packet
Once you’ve chosen the seeds you want to start indoors, the next step is to read all of the details on each of the packets. Some will require extra steps to germinate reliably.
For most types, you won’t have to do anything special. But some will need to be nicked, chilled, or soaked before they’re planted. If any of these steps are necessary, then follow the instructions on the packet.
Find The Best Location Indoors
The ideal location for growing seeds indoors is a place that doesn’t get much traffic, is between 60-75F, has good airflow, and plenty of space for everything (including allowing you to move around easily).
But really, as long as you have the proper equipment, you can use any room of the house. Even in a cool basement or a dark closet.
Prepare Your Equipment
Getting all of your equipment set up beforehand really helps to speed things up. So pull everything out of storage, and dust it off.
Set up your shelves, and hang the lights. If you have trays that you’re going to reuse, it’s crucial to clean and disinfect them first to prevent disease and fungus issues.
Now is also a great time to take inventory on your supplies, and buy anything you’ll need to hit the ground running when sowing time comes.
How To Start Seeds Indoors Step By Step
The funny thing about growing seeds indoors is that planting them is actually the easiest part. Here are the step by step instructions.
Step 1: Prepare the soil – Loosely fill they cells with soil, or soak the pellets to get them ready. Gently water the soil to moisten it. If it settles, then add more medium, and water it again.
Step 2: Plant the seeds – You can either make holes first to drop the seeds into. Or gently press them into the soil to the correct planting depth.
The general rule is to plant a seed twice as deep as it is wide. Teeny-tiny ones can just be sprinkled over the top.
Step 3: Cover them with soil – Cover up each one, and then gently pack it down to ensure that the soil comes in contact with the seed.
Step 4: Water the trays – Pour the water it into the tray, rather than over the top of the soil. Pouring water over the top could displace the seeds.
Step 5: Place them in a warm location – Put your trays in a room that is between 65-75F, or place them on top of the heat mat.
Tips For Growing Seeds Indoors
Once everything is planted, things can get a little more complicated. But this is also the best part! Here are some tips to help you learn even more about how to grow seeds indoors.
Light
For the most part, you won’t have to worry about turning on your grow lights until you start to see green in your trays. However, some actually need light to germinate.
In either case, make sure that you hang the lights only a few inches above the tray at all times. I recommend using adjustable hangers to make it easy to move them up as the seedlings get taller.
From the time the very first seed germinates, and as long as they are indoors, you should run the lights for 12-16 hours every single day. Learn exactly how to use grow lights for seedlings here.
Bottom Heat
Most seeds germinate fastest when the soil is consistently between 65 to 75F degrees. This is where your heat mat will really come in handy.
You could also try putting them on top of a radiator or air vent instead (as long as it’s not too hot). Just keep in mind that heat sources like this can dry out the soil much quicker, so watch them very closely.
The easiest way to ensure the temperature stays consistent is to use a soil thermometer. Oh, and don’t plug your heat mat into your light timer, leave it on constantly.
Watering
Keep soil evenly moist during germination. This can be a delicate balance, but basically it should never dry out completely or be soggy.
When you need to add more, pour the water into the seed tray rather than over the top. A spray bottle or mister also work well.
If you struggle with getting it right, then I recommend buying a soil moisture gauge. This handy tool really makes it simple to tell how wet the medium is.
Fertilizing
You don’t need to use fertilizer until after your seedlings have their first true leaves. Once that happens, then feed them with a weak dose of organic liquid plant food.
I recommend applying a natural fertilizer, rather than a synthetic chemical one. No only do they work better, there’s a much lower risk of burning your sensitive baby plants.
I use (and highly recommend) a general purpose liquid, fish emulsion or compost tea on all of mine. They love it!
Fish emulsion can get a bit stinky when used indoors though. So be sure to dilute it, or wait until everything has been moved outdoors before using it.
Now that your seeds are starting to grow indoors, learn all you need to know about how to care for seedlings.
Starting seeds indoors is not only fun, but it’s a great way to get a jump on the gardening season. When you grow seeds rather than buying plants from the store, it can literally save you hundreds of dollars every spring. Plus nothing is more satisfying.
If you’d like to learn everything you need to know about how to grow seeds for your garden step-by-step, then take my Seed Starting Course. It’s a self-paced, online program that will teach you everything you need know in great detail. Don’t waste another year struggling to learn by trial and error! Enroll in the course and get started today
Otherwise, if you just need some guidance going forward, then my Starting Seeds Indoors eBook would be perfect for you! It’s a quick-start guide, and it will get you up and running in no time!
More Posts About Growing Seeds
- How To Make Newspaper Seed Starting Pots
- Winter Sowing Seeds: A Quick-Start Guide
- 13 Easy Annual Flowers To Grow From Seed
- 23 Easiest Vegetables To Grow From Seed
Share your tips for starting seeds indoors in the comments section below.
Cathie says
How many seeds do I put in each hole? I have the small square cardboard pots.
Amy Andrychowicz says
It depends on the type of seed and how old they are. If they’re brand new seeds, then you can just plant one per hole. If they are old or a type of seed that has a low germination rate, then plant 2-3 per hole and thin them out later. If they’re super tiny (like specks of dust) you can just sprinkle a few of them over the top of the soil.
Scott says
I always have skinny plants and the stems don’t get thick. I use a grow light and a heat pad. Could you tell me how to grow thicker plants? Thank you.
Amy Andrychowicz says
The only way to grow thicker seedlings is to give them plenty of light. It sounds like you either need to move the lights closer to your trays, keep it on longer, or get a stronger one. Here’s a post that will give you all the information you need for how to use them properly to get strong, thick starts… Lighting For Seedlings: When To Put Seedlings Under Light & How Much.