Once you’ve decided to start some of your seeds indoors, you’ll want to get together a plan for what comes next. In this getting started guide for starting seeds indoors, we'll cover:
- Choosing your growing medium and soil
- Sowing seeds
- Watering tips
- Lighting tips
- Fertilizer - How and when to use
- Potting up
Tips for Starting Seeds Indoors
Planning is always your first step. Do you have a good space to start your seeds indoors? Some people have an extra room that they can dedicate to their new plants inside, while others start theirs out in a shed outside or in the garage. Make sure you’ve got plenty of room for your seeds and that you can keep them warm and sheltered. Consider how many outlets you’ll need for grow lights and heating pads, and how often you’ll be able to check on your plants.
Choose your growing medium & soil
Your seeds need a growing medium with a fine and loose texture that drains well.
Do not be tempted to reuse potting medium or to use soil from outside.
The indoor sprouting environment is also perfect for fungi and other diseases to flourish. Using a fresh soilless medium that you mix yourself or buy prepared ahead of time is easy and protects your seedlings from this danger.
You’ll also want to make sure your containers are sterilized if you’re reusing them for the same reasons.
Preparing your growing medium and sowing seeds
Moisten your chosen growing medium and fill your containers evenly. If using a flat, creating rows can keep the seedlings organized.
Plants that need to be planted more deeply will benefit from being grown in individual containers or cells.
Sow your seeds spaced out uniformly according to the instructions on your packages. Different seeds have different depth requirements, so make sure you give each seed the individualized attention it deserves.
Water your seeds by misting them gently. A bottom watering system can be a useful way to keep the growing medium moist without washing the seeds away.
Whatever system you choose, make sure your seeds and soil are watered evenly and never fully saturated or waterlogged.
Place a humidity dome over your seeds to keep them appropriately moist for longer. Never place domed plants in direct sunlight. Keep an eye on your seeds and pull that dome off once they’ve sprouted to prevent damping off. Water according to the needs of each seed.
Provide your seeds with the light and warmth they need to germinate properly. Heating mats and grow lights give your plants a head start on the growing season. Different seeds have different heat requirements, so make sure you take the time to make sure each heating pad is set to the right temperature for optimum germination.
Label your seeds
Don't forget to label each container so you know what you’re growing. Note plant variety and date planted on labels. Using the seed packets can help you to remember the needs of each plant in case you forget.
You’ll also want to date your seeds so you remember when you planted them. This will help you keep an eye on germination and make sure that everything is on track.
Give your young plants fertilizer
After seeds have germinated, they will need some fertilizer. Soilless mediums typically are devoid of any nutrients for the young seeds. Young tender seedlings can easily be damaged by too much fertilizer, so be careful.
Use half-strength fertilizer a few days after germination and watch your plants. After they are more established, you can follow the recommended schedule of your chosen fertilizer.
Pot up as needed
As your seedlings grow, you may have to “pot them up” or move them to a bigger container to give them more room to grow even before they’re ready to move outside. A larger container will allow the plant’s roots more room to grow without becoming rootbound or drying out.
How often you have to pot up depends on the size container you originally planted your seeds in, the type of plant, and how fast it grows.
Enjoy watching your seedlings grow from tiny seeds to thriving plants. As they grow, thin out your seeds as needed to give the strongest plants more room. It won’t be long until you’re hardening them off to move outside for the next stage in their life cycle!
Written by Teresa Chandler