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:
- Planning
- Choosing your growing medium and soil
- Sowing seeds
- Watering tips
- Lighting tips
- Labeling
- Fertilizer - How and when to use
- Potting up
Tips for Starting Seeds Indoors
Planning
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.
Make Your Own Seed Starting Mix
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.
Choose Reliable Heirloom Seeds
Watering tips
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.
Lighting tips
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
How to Start Seeds Indoors: The Complete Guide
Hardening Off Plants: Toughen Up Your Babies for the Real World
FAQs
Not every vegetable should be started indoors. There are many varieties that can be planted right into the ground (direct-seed). These are usually the short season vegetables or root crops that don't always transplant well. They include lettuce, spinach, beets, carrots, green beans and others.
What seeds should not be started indoors? ›
Not every vegetable should be started indoors. There are many varieties that can be planted right into the ground (direct-seed). These are usually the short season vegetables or root crops that don't always transplant well. They include lettuce, spinach, beets, carrots, green beans and others.
What is the best soil mix for starting seeds indoors? ›
The most convenient type to use is one of the commercial soilless mixes (Jiffy-Mix, Pro-Mix, Redi-Earth, etc.) that contain peat moss, perlite, vermiculite, and usually some fertilizer (see Table 1 for a mix recipe). These are specially formulated for starting seeds indoors.
How long should I leave a fan on my seedlings? ›
I keep the fans moving across the surface of seed trays throughout the eight weeks of their development. That's not absolutely necessary. You could opt to turn fans off once the seedlings have developed their first true leaves. I've just found the best success with continued air movement throughout the process.
What are the easiest vegetable seeds to start indoors? ›
Tomatoes, Peppers, Eggplants, & Tomatillos Are Easy Fruiting Plants to Start Indoors. Since you have to leave these plants in your garden long enough for them to form and ripen fruit, you definitely want to start them early so that you can maximize their growing time outdoors.
What month do you start seeds indoors? ›
March is a great time to start seedlings indoors. Generally, start planting seeds indoors 6-10 weeks before the last frost date. Michigan's last frost date is generally recognized as May 15th. Seeds are best sown directly in the garden when the soil has warmed to approximately 70 degrees.
Should you soak seeds before planting indoors? ›
If you're storing and sowing seeds inside, they won't go through a cold winter, which some need to signify it's time to wake up and grow. To ensure high germination rates, wake seeds up, and potentially speed up the process, soak seeds before sowing them to soften and loosen that outer protective layer.
What veggies should I not start indoors? ›
Pay attention to the backs of seed packages, which will often tell you if a plant is not recommended for indoor seed starting. Typically, those plants have tender root systems that are easily disturbed by transplanting. Plants that don't like to be moved include small leafy greens, root crops, beans, and some peas.
What seeds should not be soaked before planting? ›
By soaking the seed, it enables the new growth from the inside to push through the hard shell and grow. The seeds that could benefit from a good soaking include: corn, pumpkin, beans, chard, beets, and peas. The seeds you shouldn't soak include: carrots, lettuce, radish, celery, turnips, and spinach.
Can I use potting soil as seed starting mix? ›
While some gardeners do use potting soil for starting seeds, you might want to take into account what type of seed they're using. When you sow seeds large enough for a potting mix, you're sowing seeds that should be about the size of your pinkie fingernail.
Help seeds germinate by sowing them in Miracle-Gro® Seed Starting Potting Mix. This is finer than a regular potting mix, so young roots have an easier time of poking through. It mostly contains lightweight peat moss—a texture that allows air to move through while retaining a uniform amount of moisture.
Can you put seeds straight into soil indoors? ›
You can germinate vegetable or flower seeds indoors in early spring using a few basic tools. This gives plants more time to mature before you transplant them outdoors, which can be critical to their survival in colder climates.
Do seedlings grow more at night or day? ›
In the presence of light, plants direct their growth toward the light. The growth that occurs at night tends to be vertical, unaffected by this daytime tendency to reach toward the light. Some plants may even grow faster at night because during daylight they focus their energy resources on photosynthesis.
How to keep seedlings happy? ›
Keep your soil moist, but try to avoid soaking it. As your plants' root systems develop, they will take up more water each day. Your potting mixture will also determine how well water drains from your system. Overwatering can also create soil conditions where small insects like fungus gnats thrive.
Can you use egg cartons to start seeds? ›
You can use egg cartons as a seed-starting tray! Depending on the type of carton you have, you can even cut apart the individual sections and plant them, as the carton will biodegrade. Be sure to poke small holes for drainage, and put the cartons on a tray or in a shallow pan to catch any residual water.
Should I soak seeds before planting? ›
It is traditional to soak some seeds before planting them. Soaking can accelerate germination and increase the proportion of seeds that successfully germinate. Seeds have evolved a protective coating around the embryo so the embryo can survive being dispersed by some means.
What equipment do I need to start seeds indoors? ›
A spray mister to keep your seeds damp until germination. Inserts for the trays to plant your seeds in, such as 6-packs or a soil blocking tool. Seed starting mix or potting mix as well as your seeds. Heat mats for warm season crops such as tomatoes and peppers.
Do I need a grow light to start seeds indoors? ›
The natural light from a window is seldom enough for good, strong seedling growth. They will usually stretch and lean towards the light and will not produce sturdy plants. Sowing seeds indoors under fluorescent lights is the easiest way for the home gardener to control growing conditions and grow healthy transplants.
