Growing seasons differ across the country. A lucky friend of mine just sent me a picture of the lemon and orange trees in her yard that are in full fruit right now, living in southern California makes a big difference I suppose. The weather here is still touching on freezing overnight and with as mild as the winter was it would not be remiss to expect it to keep going this way for another month or even two.
I recently picked up an indoor/outdoor thermometer with min/max capabilities to keep an eye on how much the temperature in my tiny greenhouse is changing. In the past week the minimum temperature inside the greenhouse was 33 degrees, and the maximum was 96. Unless one of the kids slapped the thermometer with a hot potato when I wasn't looking, that means there was a more than 60 degree change in temperature just within the week. Too cold for winter veggies and too hot for them too. I definitely need a better greenhouse system, but I'm unwilling to invest in one since I have such limited space. Instead the greenhouse will be used solely for hardening off, opening it up during the day and closing it on cooler nights to keep the temps from going out of control.
This has left me in need of a space to get my winter veggies started. My brother, may his awesomeness reign forever, has agreed to start my hot weather plants for me again this year. I plan to attempt starting the cold weather plants myself though. With that in mind I decided to build a "grow room"... er, shelf inside.
People give you a lot of strange looks when you mention that you are building a grow room, it seems the phrasing just makes them think of growing marijuana, but in actuality it makes good sense (cents?). Starts from a nursery are often limited to the most common varieties, and by what is in stock. Each start you buy ranges in price from .99 to $5.00 (for gallons). But if you have a grow room and some seeds you can effectively pay far less in the long run and have better quality plants of more varieties. If you save your own seed it cuts the cost even further.
So let's talk about the costs of a grow room. For cool weather plants the costs are lower than for hot weather plants, primarily because you don't have to heat them as much. Start with a shelf, or shelves, or a tabletop, or a windowsill, anywhere you can find room to set one or more trays of pots, hang a light over it, and keep it away from things or people that could cause trouble. You will need lighting, if it's a completely enclosed space you'll need ventilation, if it's outside of the house or you will grow hot weather plants longer than a few weeks you'll need a heat source you can monitor and adjust. You also need trays, pots, potting soil, seeds, water, and a power source for the heat/lights/ventilation.
For example, my "grow room" will actually be a few shelves in my laundry room. The furnace and back door are in there, and it is generally left open to the rest of the house so ventilation and heat should not be an issue. There is a power source (the outlet the washer is plugged into) to run the lights, though I will need a power strip to use more than one light at a time. Currently I have a small metal shelving unit in there which holds the overflow of my Costco shopping trips that won't fit in the kitchen. My plan is to replace this with a 4 tier shelf that is wider and taller. It will still hold my overstock goods in the bottom two shelves, but the upper two will be outfitted with lights and house my starts.
36" wide 4 tier shelves: $60
Power strip: $20
2' wide single bulb flourescent light fixtures: $10 each
2' long flourescent light bulbs (daylight or plant and aquarium): $8 each
Plastic seedling trays: $2 each
Organic seedling potting mix (small bag): $5 each
Aluminum foil: $5
Newspaper/reusable old pots/phone book: $0
Depending on how many plants you plan to start it should have an initial cost of about $150 or more. Nearly half the cost is just the shelving unit, which is totally reusable year after year and can be used for storage between growing seasons. The other big cost is the power strip and it can also be used year after year, or used for other things when it's not needed for the plants. The light fixtures and plastic trays should last you a few years too.
The things that need replacing each year are the potting mix, aluminum foil, cardboard and pots. But cardboard is free from any recycling bin, aluminum foil is inexpensive, potting mix can be made in bulk, and pots can be made of free recycling items too.
So, to make the cost comparison, let's say you are planning to grow cabbage, broccoli, kale, onions, and carrots. About 70 plants total. To buy these plants already started you'd pay about $2 each for four packs of the larger veggies or 6 packs of the smaller ones. For this price you get the smallest starts, basically a stem with its first set of true leaves. If you want 40 of the large veggies it will cost $20 and let's say about another $10 for 30 of the smaller ones. So you spent $30 on starts. Not so bad really, in fact, I know I usually spend more than this... maybe I underestimated the cost. But no matter. 4" potted starts will cost you up to twice as much for one plant.
The first year of building a grow room you will have spent $150 on the setup alone, and about $7.00 for the same five types of plants. The difference is that a packet of kale seeds contains around 50 seeds, carrot packets contain closer to 100 or more. So instead of 70 plants you have the ability to grow 250 plants. You can grow spares and sell them, or trade them to other gardeners, or share with friends or family. Or you can save all that extra seed for the next year and save yourself the seed costs. Obviously there is no savings the first year, but the second year you only have to pay... well, nothing if you make your own potting soil from your own compost, about $5-$15 if you buy it, depending on how much you need. And so on, for many years. Light bulbs will need to be replaced every few years, and undoubtedly your plastic trays will eventually need replacing, but for the most part the grow room will be low maintenance and save you money in the end.
Considering I spend $150 on seeds alone, of nearly 40 different plants, if the grow room will allow me to improve their survival rate and possibly even turn a few starts into cash by selling them to neighbors or my mom at a discount I will be happy with the investment. Two shelves of grow space alone should provide all of my cool season crops adequate room, and it could also be enough space for the hot season plants if needed (after the cool plants were moved outside). Imagine how much you could grow in a whole room!
The other big bonus to creating your own grow room is getting ahead of the game on planting times. In the Willamette Valley a gardener has between April 15th and October 1st to do all of their growing. Just over 5 months. If it takes a cabbage 60 days to reach maturity and a tomato 80 days... there just isn't enough time to plant one from seed and then follow it with the other from seed. Working in a small space you can really increase your returns by planting the same area twice, or even three times, in one season. With a grow room I can start my cabbages inside a month earlier than I could outside, while the soil is still too cold for germination. They can grow larger under optimum conditions before being put outside, then finish their growth in the garden where they will have plenty of room. This means that I should be able to have the cool weather crops (or at least most of them) harvested and pulled out in time for the hot weather plantings to go in at the beginning of June. Then I can even start a fall crop in August when the determinate tomatoes have finished producing and the basil is harvested, leaving the longer season tomatoes to finish off before it gets cold again.
Lastly, I can use my grow space over the winter to grow entire plants for fresh eating indoors. Spinach, lettuce, green onion, annual herbs like cilantro and basil, all of these can grow indoors over the winter. They won't outgrow their space and can easily be harvested as needed without sacrificing the entire plant. Inside a house they shouldn't even need extra heat to stay healthy.
P.S. I almost forgot to explain the purpose of the foil, cardboard and newspaper etc. Backing and/or siding your shelves with a reflective surface (i.e. aluminum foil wrapped over cardboard for stability) will help keep the light and heat focused inward toward the plants and can make a big difference in plant health. Newspaper or phone book pages make excellent paper pots, or you can reuse any old start containers from previous years, just be sure to wash them well with soapy water. I've found that newspaper origami pots are about a 4" pot, while phone book pages make a pot closer to the size of a 2" peat pot. Yellowbook phone books are totally recyclable and have soy based inks that won't contaminate your soil, check online to see if your phone book is made with soy based inks. If not, stick to newspaper, which is always made with non-toxic inks.
Next time... When the Men Are Away, the Women Will... Build a Grow Room?
In which my daughter and I put together our grow room, start seeds, and then wait for my husband to notice it when he gets home.