Sowing Seeds Indoors

Sowing Seeds indoors with Sensible Gardening

I may be sitting indoors watching the snow fall around my garden, but my mind is elsewhere. My favourite seed catalogs have been arriving in the mail and I’m secretly planning what I want to grow this year. I’m sure I’m not alone. Sowing seeds indoors, usually starting in January, is what makes it possible for me to get through the dull cold days of our winter.

Success in sowing seeds indoors is not a given. There are things you must pay attention to in order to have rewarding results. Many hardy seeds can be planted directly into the garden during early spring, but for those tender plants you will have to work a little harder.

Timing is Everything

When you are sowing seeds indoors, timing is very important. Each plant has a time schedule for when to start the seeds so you produce healthy seedlings at the appropriate time for transplanting outdoors. You don’t want to be too early or you will end up with leggy week transplants. If you are too late then your transplanting dates will be past the due times. A great source of this information is given on your seed packet. It will tell you when to start the seeds, the number of days they take to germinate and best sowing date.

Sowing seeds indoors with Sensible Gardening

If you have plans to grow a variety of different plants it’s best to make yourself a simple seed sowing calendar.  First find out what your average last day of frost is in your growing area. From that date work backwards the number of days that seed requires to germinate and grow before being planted outdoors. Start your seeds around that date. For finicky seeds that need some pretreatment such as chilling or soaking, you will have to factor this time as well into your schedule.

Example of seed growing Calendar for Sowing Seeds Indoors

Plant         Pretreatment           Start Date          Germination Date          Transplant Date




Indoor Growing Sites

If you are a very lucky gardener, you might have use of a greenhouse. This is on my wish list but not possible at this time. Instead you can make due with a bright south-facing window. Not without it’s limitations and problems I use a few tricks to make the window location more suitable for growing. Our winters are dry and cold. To protect the seeds from winter night drafts by the window I place a cardboard barrier between the window and the pots at night, removing it in the morning.

Sowing seeds indoors with Sensible Gardening

Our indoor air is very dry so to raise the humidity which most seeds prefer, I place cleat plastic covers over the pots or seed trays to hold in the moisture. Keep a close watch on these and lift or remove if too much moisture develops as your seeds could then rot or be prone to diseases.  I also use a room humidifier, this is also very good for the house inhabitants.

Artificial Light and Heat

Sowing seeds indoors with Sensible Gardening

Another option that is affordable is to use artificial growing lights. This allows you to set up a table or work bench with trays or pots and supply some type of artificial light. Fluorescent lights work well, as do cool white or violet grow lights. You can make up a DIY set up or purchase a ready made fixture to place over your seedlings. Most seeds also prefer bottom heat for germination. Affordable electric bottom heat growing pads are available, which you simply place underneath your trays. Optimal temperature is between 70 and 80 degrees F, or 21 to 26 degrees C.

Growth Medium ( Soil )

As much as you think your garden soil in ideal, do not use it when sowing seeds indoors. You will find instructions on how to sterilize it, but it’s a lot of messy work and not worth the time and trouble. Using garden soil is an invitation to all sorts of pest and disease problems.

Sowing seeds indoors with Sensible Gardening

Instead, buy bagged pre-mixed seed starter mix or create your own. Most sowing media you buy are soilless blends of perlite, vermiculite and peat moss or well sifted compost. You want  a sterile mixture that holds moisture and air with a fine texture.

Damping Off

Damping off is the process where seedlings wither and die from fungal diseases. Unfortunately once damping off starts it is unrelenting and cannot be reversed. This is why your growth medium needs to be sterile, pest and disease free.

Pots and Trays for Sowing Seeds Indoors

You can start seeds in just about anything that has good drainage ability. Plastic and clay pots, plastic trays, peat pots, milk cartons, tin cans, newspaper pots and the list goes on. Whatever you choose to use just be certain that everything is as clean as you can get it.

Sowing seeds indoors with Sensible Gardening

If you are reusing pots, they must be washed in a solution of dish soap and rinsed in a 5% solution of bleach and water. Also any container you use must have good drainage.  Seed trays work well when you are sowing a lot of the same thing.

Sowing seeds indoors with Sensible Gardening

Fill your pots right to the top with your growing medium and give it a good solid tap on the table to settle the mixture and remove air gaps. You might have to add a bit more mixture to the pot at this time to bring the mix level back up to the very top.

More info to Help you with your Seed Starting and Growing

Check out some of these other posts which are full of information on all the stages of starting and growing your seeds indoors:

How to Start Seeds

How to Transplant Seedlings

The Scoop on Grow Lights

How to Rescue your Seedlings

How to Grow Seedlings

(Photos from Pixabay)


Sowing Seeds Indoors with Sensible Gardening

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About Lynne Cherot

It's been a life time of gardening and many years of working in the nursery trade, but now I enjoy exploring and creating in my own gardens and farm fields . I'm passionate about gardening and work alongside my husband who takes care of our apiary. Bees & flowers make a great team! Hopefully by sharing my garden knowledge, your gardening will be easier and more enjoyable.
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