Top 5 tips for starting seeds indoors in winter

When fall and winter arrive, it is time to start planning your indoor garden.

To start small, you only need a pot, seeds, potting soil, water, and light. And I do recommend starting small and getting a feel for the process.

Why?

Well, growing indoors in low-light conditions does pose its own set of challenges. And you can learn a lot when starting small with a plant or herb like chives suitable for low-light indoor conditions.

Seeds sprouting fresh first leaves on the counter in the kitchen
First leaves sprouting and see below for more.

Here are the top 5 tips you need to be aware of to grow herbs and vegetables indoors in the wintertime successfully.

Tips for indoor gardening in the wintertime

If you are interested in learning more about hydroponics, please start with the article Hydroponics for beginners. Here you will learn the basics of hydroponics and find step-by-step tutorials on how to build your own DIY hydroponic grow system on a budget.

1. Pick a herb or vegetable suitable for indoors

When deciding on a herb or plant to grow indoors, there is one critical factor to consider.

Will you rely on natural light, or are you planning to use grow lights?

If you are using grow lights, you can grow most herbs and vegetables. Our top picks include different varieties of basil, rocket or arugula, and sage.

Coriander or cilantro is a favorite winter herb to grow indoors
Coriander or cilantro is a favorite winter herb

Whereas if you rely on natural light, you must select herbs and vegetables suitable for low-light growing conditions. You can find the top 5 picks in the article How to grow herbs indoors in winter (without grow lights).

2. Be smart with the light available to you

Plants need light to grow. It is as simple as that. 

And if you are planning to use grow lights, you are all set. Give your plants a minimum of 10-12 hours of light, but remember that plants also need a dark period.

But you can grow indoors without buying grow lights. But you need to adjust your expectations and work with the light available to you.

Adjust your expectations

You must adjust your expectations as you will not get the same yield or harvest without grow lights. But that is fine. You will still have plants to harvest.

Be smarter with the available light 

You will be able to grow and harvest fresh herbs and vegetables if you are smart with the light that is available to you.

Use smaller-sized, mobile pots and containers and move your plants to where there is natural light during the day. Place your pots or containers in the most well-lit areas of your house at night. 

Remember, every little bit of light helps.

3. Use potting soil or another medium that drains well 

Like regular outdoor gardening, it is vital to use well-draining potting soil. 

If you are using regular potting soil, mix it with perlite or coarse sand to create a lighter, more well-draining potting mix. 

If you are planning to buy potting soil, look for a lean well-draining cactus-type soil mix.

As always, your plants want a moist but not wet growing environment.

4. A helpful hand germinating the seeds

You will have a better germination rate if you keep three simple things in mind.

Seeds want warm soil to germinate

Now, warm does not mean piping hot. You are looking for a soil temperature of about 21-24 degrees Celsius (70 to 75 degrees Fahrenheit).[1]

You want to warm your pots from below, and you can either use a heat mat or place the pots on an appliance like a refrigerator that radiates heat.

A window sill on top of a radiator can also work but remember that you are looking for warm and not hot. Too hot, and you will kill your seeds before they sprout.

Place pots in a cooler spot when you see the first leaves sprouting.

Cover your pots with plastic

Covering your pots with a plastic lid or placing them inside a plastic bag will help create a warm and moist microclimate.

Do not cover the pots hermetically. Poke holes in the plastic to ensure air can circulate. If condensation forms, remove the plastic and poke a few more holes in the plastic before placing it back over the pot.

Keep plastic cover until you see the first leaves.

 Larger vs. smaller-sized seeds

As a rule, you place smaller seeds like mint on the surface. Use a spray bottle to mist the seeds gently. 

Larger seeds like coriander do, however, benefit from a little bit of help. 

You can place the seeds in room temperature water for 6-8 hours before planting or gently crush the seeds to break the hard shell.

This little extra effort will speed up the time needed for germination significantly.

5. Do not overwater and go easy with fertilizers

Plants growing indoors in low-light conditions grow slower and need less water than you think.

Be mindful not to overwater, as your plants are more likely to die from overwatering than a minor dry-out. 

The same goes for using fertilizers for established plants. Use a quarter of the recommended dosage and then observe and adjust.

Bonus tip!

Plants growing indoors in low light conditions tend to grow leggy and typically produce a lower yield or harvest than you are used to from your garden.

Still, following a few simple rules, you can harvest fresh herbs and selected vegetables throughout winter.

Same pot as above and now we start seeing the forming of true leaves
Same pot and if you look closely we see the start of true leaves.

Pinch back and harvest established plants regularly. Pinching back will help promote a more compact and bushy growth resulting in a healthier and easier-to-look-after plant.

Helpful resources:

[1] https://hortnews.extension.iastate.edu/faq/what-optimum-temperature-when-germinating-seeds-indoors

Mattias Magnusson: Hello, I'm Mattias, a passionate and experienced gardening enthusiast. I am the creator of MattMagnusson.com, your guide to year-round herb and veggie growing. Let's simplify green living, no matter your space or location.