Greenhouse Chores for March

March is that time of year where it can be both winter and spring. For the gardener this time of year in zone 5 is when we start seeds for the summer vegetable garden. This means a lot of March should be spent in the greenhouse. Here are some chores that should be done in the greenhouse for March.

Preparing for seedlings

I start all my seedlings under a grow light indoors before I move them to the greenhouse. I do this because it costs too much to heat my greenhouse when it is still frigid outdoors. Even though my greenhouse will get warm at midday it does not hold much of the heat, and requires a heating source.

Greenhouse seedlings — Here are some of my seeds popping up in the greenhouse

In March you should start cleaning up the greenhouse to make room for seedlings. Here is a list of chores to clean up your greenhouse:

Sweep the floor: Your greenhouse most likely got dusty and dirty over the winter. Clean up all the dead leaves as these could spread pest and disease problems to other plants.
Pull up dead plants: In my larger pots I let the annual plants die back for the winter and then pull them out in the spring. As long as these plants did not have any pest or disease issues you should compost them.
Clean pots: Your pots most likely got dirty over the winter; a quick wipe on them will make your greenhouse look sharp.
Check heaters: I will move all my plants out next month (April) so make sure that your heaters work well. It is a must to keep your seedlings at or above 50^oF at all times or they will suffer. If you are using heating pads for things like peppers you will want to check them too.
Reinstall window openers: If you have automatic window openers reinstall them and calibrate them so that they open at the right time.
Buy potting soil: I like to buy organic potting soil that has microorganisms that benefit the soil life. I will use this potting soil to pot up my seedlings.
Get Fertilizer: When you start to pot up your seedlings you will need fertilizer for them. In my greenhouse I use fertilizers like Epsom salts, fish emulsions, or compost. You can also rejuvenate old potting soil by adding compost to it.

How to heat your greenhouse

I use an electric heater in my small greenhouse. It will keep the heat at or above 50^oF even when it is below freezing outside. My heater is a 5,000 watt space heater. Make sure that your heater is not close to flammable substances.

Greenhouse in march — You can see both my heater and the blue tote full of water

Another way to help heat your greenhouse is passive heat. This is the heat that you get from the sun. It is amazing how warm your greenhouse will get just by the sun alone. Mine can reach 100^oF when it is only in the 20s outside. The only problem with this heat is that it does not hold in a small greenhouse. Some you can hold this heat in the greenhouse over night is with heat sinks.

I use a dark colored tote and fill it with water. The water will get warm during the day and release it at night. This might not keep it warm all night, but it can help you run your heater less. Here is an article on all the things you can use as heat sinks.

Plants you can grow in the greenhouse in March

Though you won't be able to grow tomatoes in your cool greenhouse you can grow other things. Here is a list of plants that can grow even when the temperature reaches around 26^oF.

Collards
Cabbage
Kale
Beets
Carrots
Lettuce
Chard
Endive
Parsley
Cauliflower
Brussel Sprouts

As you can see there is a whole group of plants that won't fuss about the cold weather. Take advantage of your slightly warmer greenhouse and grow some greens this March.

Clean garden tools

Cleaning and taking care of gardening tools will help them to last longer and cut better. I will clean my garden tools with rubbing alcohol to clean off plant residues and rust. You can also add lubricant to keep them working smoothly.

Collect snow

Snow is also known as poor man's fertilizer. It has a small amount of nitrogen. I will collect this in buckets and then use it on seedlings for a boost.

Snow in a bucket — This snow will make a great "soft" fertilizer

Final thoughts

March is the time to get your greenhouse in shape for seed starting. You should clean up your greenhouse and get all the supplies you will need for the spring seed starting time.