This might help with understanding my green project.
Summarized by myself.
All information was taken from the Hotbeds and Cold Frames paper. Written by Michael N. Dane and B. Rosie Lerner.
Hotbeds and cold frames are used for extending the growing season of plants in both the spring and the fall. The major difference between the two structure types is the source of heat. A cold frame relies on the sun for its warmth whereas a hotbed uses a secondary heat source as well as the sun (manure, electric, flue-heated, steam or hot water heated). Plant performance in a hotbed is better but more energy is needed after the initial build then a cold frame.
Both frames give a great advantage to the small farm. The same site selection is necessary for both structures. A well drained, south facing out of the wind location, with a water source is crucial. Proper ventilation not only helps plants with fresh air, it keeps the humidity down and disease out. This can be done by opening the frame for increasing times as the season goes on.
When building your cold frame the best method uses at least two sections. One side with good ventilation and one side sealed good from the elements. Different plants/Different stages of the same plants life require different living conditions.
When building your hotbed the most sustainable method is using manure. Dig the inside of your structure down 18”. For drainage the first layer is 4” of gravel and then fill the rest in with manure (go to about 1”above the ground level). Because you seed directly in the soil (not in pots) you will then add soil high in organics for your top growing mix. A chemical reaction happens between warmer temperatures, water and the manure to create a secondary heat source. Keep an eye on the temperatures with a few thermostats and not allowing it to go out of the 18-25
°C range. Nights may require a straw mat (insulation) to keep the temperatures high.
Never think that anything can only be used for one purpose. Growing cool season crops in the fall is a great idea. Another good winter vegetable storage for apples, turnips, beets, carrots, ect is a cold frame.
ALSO! This is my orginial pitch for my hotbed idea.
This is step 1. I'm going to try this this winter as my "Green Project" at school.
- Pick a crop you want to specialize in
- What type of greenhouse/coldframe structure would you use to propagate/grow your crop
- Identify the growing conditions your crop requires and how it correlates to your chosen structure
- List the various components of your structure and how they function
1) Crops to specialize in: Arugula, Chard, Kale, Lettuce, Mustard, Spinach, Mesclun mix, Cress, ect
2) A hotbed would be the most functional structure for growing any of the salad greens during the winter months. Temperatures don’t need to be nearly as high as for other crops because salad greens are cool season plants. Using manure as a heating medium should do for the entirety of the winter. Propagation is not necessary for these crops. All of them can be directly seeded in intervals to give a continual supply.
3) All of the crops chosen are cool season crops, usually grown in spring and fall in Nova Scotia. If you are looking for a sustainable lifestyle or a way to prolong your crops for sale you want to be able to produce in the winter. These crops are unable to be grown in the summer. Using a hotbed during the winter months would give the grower the ability to grow greens for 3 of the seasons making your home or business more profitable. Light levels are lower during the winter months thus giving less of a yield but face the hotbed south and you will still have enough light to allow the plant to grow.
4) Hotbeds can be as expensive or inexpensive as you wish. I’m going to profile a hotbed that would be inexpensive to make and still profitable. Building a box with a top that opens is key. You want to the structure to allow as much light in as possible without allowing the valuable heat to leave. You can use plastic, glass, or fiberglass. You also want to structure on a slight downwards slope to give yourself good drainage and maximum solar absorption. Having a wind block (hedge, build your structure off of a building, ect) to the north is also good to help cut down on the cold winter winds. You want to use every source of energy you can so building your structure into the ground a little ways is a good idea to help with insulation. You can use different methods to heat your hotbed during the winter months: Oil-heating cables or steam-carrying pipes are a more expensive method but your results will be better. Fresh manure buried beneath the rooting zones of the plants is an organic method using products we already have. Keeping the manure moist will allow a chemical reaction to happen producing heat. Both of these methods work hand in hand with solar energy.
Chris Gillespie
