How to Garden Indoors

Surprise!  We got four inches of fresh snow yesterday in Minneapolis, Minnesota.  It was just as a subtle reminder that we are not finished with winter here in the Upper Midwest.  Although we had some really nice weather in February, Old Man Winter is not done kicking us around.  People in Zone 4B (the Twin Cities area) have a last frost date around May 10th, so we cannot even think of planting outside unless we have a heated greenhouse.  We are forced to garden indoors.  In this article, I will show you how to garden indoors by focusing on the three basic elements to growing plants: light, soil and water.

Growing Tip: To find your last frost date, go to these links if you live in Canada or in the USA.

Light

Unless you are growing mushrooms, you need to provide light to your seedlings and plants.  As discussed in the post titled Winter Care for Indoor Succulents, the sun is lower in the sky in winter months, and there are less hours of sunlight. If the plants cannot get at least eight hours of quality sunlight per day, you are going to need to switch to grow lights.  There are a lot of options out there, and I am going to focus on inexpensive shop lights, LED lights and timers that control them.

Inexpensive Shop Lights

Since I grow plants in my basement, I am forced to use grow lights on timers.  I use four shop lights that are outfitted with T12 UV bulbs like the ones pictured above.  In each shop light fixture, I use one normal T12 UV Sylvania bulb and one Sylvania 40-watt T12 Grow Fluorescent Light Bulb.  I had used the Sylvania 40-watt T12 Grow Fluorescent Light Bulbs a lifetime ago when I had aquariums full of fish and plants, and I knew they would work for vegetables and herbs.  All bulbs and shop lights came from Menards.  I paid less than $7 for my Sylvania 40-watt T12 Grow Fluorescent Light Bulbs, and you can buy packs of 6 for less than $25 online.  These have served me well for the past three years.

For shop lights, I use the lowest cost ones I can find at the local store.  These T12 shop lights typically cost less than $20, and I have accumulated four shop light units over the years for the shelves in my growing area.

LED Lights

There are other lighting options out there of course.  Jack Spirko from The Survival Podcast recommends the Kingbo Reflector 45W LED Grow Light.  It costs around $35 on Amazon.  I have not used one of these, but it is an option if you have the money to spend.  Below is a video showing the Kingbo Reflector 45W LED Grow Light in action.

Timers

While we are on the subject of lighting, you will need to put your lights on a timer system.  The timer will automate the lights since you want to give your plants 14 to 16 hours of light.  I give the plants around 16 hours of light per day (6 AM to 10 PM).  Darkness is also important for plant growth, so this gives your plants at least 8 hours of total darkness a day.

Life gets busy.  The best way to manage the lights is by putting them on simple timers.  I purchased a simple timer from Menards or Home Depot a couple years ago, and it cost less than $10.   Both shop lights plug into the timer, and you set the correct time.  Then you select the “stops” where the light turns on in the morning and turns off in the evening.  It is a really simple system that works well.

Soil

There are a lot of options when it comes to soil.  People have take soil from their garden, purchased potting soil from the big box stores, created their own mixes; or used other soil material like Coir.  To be honest with you, I have used all of these methods EXCEPT Coir.  Here is what I have learned from my experience over the years:

• Soil from the Garden – While it is tempting to use soil from the garden, the fact is that there is bacteria and other critters that you might not want to expose to your tender seedlings and indoor plants.  I ran into this when I brought plants in from outside, and in a short amount of time, aphids were attacking my spinach and lettuce.  I lost all of the plants as the aphids multiplied faster than I could eliminate them.  I do not recommend brining in soil from your garden even though it is free.
• Potting Soil from Big Box Stores – Stores offer pre-packaged soil such as Pro-Mix and Master Gardener Premium Potting Mix.  These soils work well, and they are relatively inexpensive (cost less than $10 per bag).
• Creating Soil Mixes – I have combined the potting soil with store-bought compost and vermiculite to create my Square Foot Gardening-style soil mix.  One problem I have had, however, was using cheap compost.  The compost turned out to be clay, and I could not use it.  Be careful with cheap bags of compost at the big box stores.  The drawback from creating a soil mix is that you are adding cost: potting mix is less than $10 per bag, vermiculite is around $4 per bag, and compost will cost around $5 per bag.  You are essentially doubling your cost; is it worth it?
• Coir – Coir is a concentrated seed starting mix made from natural coconut fibers.  It comes in a brick and costs less than $3 per brick.  Coir expands to 8 quarts of growing medium when 4-1/2 quarts of water is added to the brick.  I have never used this material, but I bought a brick to test it out this Spring.  My friend Emily from Pass the Pistil uses it to create her own mix, and I have linked to her video below.

I am going to be testing the two soil mixes shown at the start of this section and the Coir this year.  More on that later!

Water

As I discussed in the 8 Steps to Starting Plants Indoors article, soil has bacterial and molds in it.  Under the right conditions, you can activate those molds and damage or kill your plants.  One of the biggest culprits that I have dealt with is damping off disease.  Keeping this devastating disease in check requires using warm water, heating pads and a bottom-up watering approach.  What do I mean by bottom-up watering approach?

I am referring to “wicking,” and it is a term and method I am going to use a lot in the future.  Wicking is where the water travels through the soil using a physics property called capillary action.

For our seed trays and wicking beds, water is placed in the plastic tray that the seed containers are sitting in. The water is soaked up through the bottom holes and into the soil mix. In my experience, you only need to fill the tray about a quarter to a third full of water. Don’t over-water your plants as it will encourage mold or fungus.

It takes a while for the water to work its way to the plants, but this method really does work.  I have used this method in my gardens last year, and I will be expanding on this method in future raised beds.

Heating Pads

Plants like peppers and tomatoes want the soil to be around 70 degrees Fahrenheit before they sprout (optimal range is 70 to 95 degrees Fahrenheit).  They can be pretty finicky in a cold Minnesota basement!

I have three HydroFarm Heating Mats that I purchased for around $25 per pad.  They work really well, and the pads have helped me grow some great tomato and peppers seedlings in the past two years.  I recommend getting heating pads of some kind.  As an aside, I have used these pads to help homemade wine ferment and keep trays of food warm!  They really are fantastic pieces of equipment for your indoor garden!

When using seed trays with heating pads, check the moisture of the soil once a day.  The pads will heat the soil, and moisture will evaporate over time.  You will need to check the soil once per day to make sure it is optimal for growth (slightly damp, not soaking wet).  Be careful, too much water will create other problems!

Next Steps and Your Turn!

This was certainly a lot of information!  The next step once you have assembled this gear is to set up your growing area.  That is our next article in this series, and I will link to it here.

I hope you found it useful and picked up some ideas.  Maybe you have some ideas and tricks for your indoor garden.  Feel free to add your comments and questions below!