| Passive heating is one of two greenhouse heating | | | | - Concrete, blocks, paving slabs and rocks piled inside |
| methods, the other one being the active method. | | | | a metal cage |
| The main difference between the two is on the | | | | - Plastic barrels with lids are filled with water to the |
| power source. Where passive heating relies on the | | | | brim. One side is painted black and the other side is |
| power of the sun, active heating depends on the | | | | painted white. The white side faces the plants in the |
| power of electricity to generate heat. | | | | greenhouse while the black side catches the rays of |
| Pros and Cons | | | | the sun during the daylight. Keep in mind that black |
| From this main difference can be inferred the | | | | retains heat while white reflects it, thus, the |
| advantages and disadvantages of each heating | | | | arrangement. |
| method. On one hand, the passive heating method is | | | | - Compost and well-aged manure can be used to |
| more eco-friendly and more cost-friendly in the sense | | | | create hotbeds, which should also deter flies from |
| that little to no electricity is required. However, it is | | | | coming into the greenhouse. |
| very dependent on the strength of the sun's rays | | | | Of course, there are garden tips to maximize the use |
| such that it is virtually useless during the winter | | | | of the greenhouse heat sinks! |
| months when the sun is at its weakest. | | | | 1. First, you have to use non-reflective black and |
| On the other hand, the active method requires | | | | white paint on the barrels. This way, the maximum |
| electricity to operate, which can be costly, | | | | amounts of the sun's rays are absorbed into the heat |
| complicated and not exactly eco-friendly in general. | | | | sink. |
| However, you cannot discount the fact that it can be | | | | 2. Second, make sure that the heat sinks are facing |
| used during the hard winter months when the sun is | | | | the sides of the greenhouse where there is |
| nowhere to be seen. | | | | maximum sunshine. This often means the |
| Harnessing the Pros | | | | south-facing side although you have to observe your |
| Still, despite the above mentioned limitations, | | | | area to determine said site. |
| greenhouse gardeners use passive heating to | | | | 3. Third, the heat sinks must be located inside the |
| improve plant growth especially during the summer. | | | | greenhouse and slightly away from the sides. This is |
| The trick is in harnessing as much solar power as | | | | because the glass panes of the greenhouse can |
| possible, of which heat sinks can greatly help with. | | | | quickly absorb the heat being emitted by the heat |
| Simply put, a heat sink is any kind of material that | | | | sinks during the night, thus, negating their value for |
| allows the heat absorbed during the day to "sink in". | | | | the plants. |
| During the night when temperatures around the heat | | | | 4. Fourth, you can wrap the north side (or whichever |
| sink are cooler, the trapped heat is slowly released, | | | | side is receiving the least amount of sunshine) with |
| thus, providing for more warmth. Ultimately, the | | | | bubble wrap. This way, more heat is retained inside |
| plants are provided with heat despite the surrounding | | | | the greenhouse. And it helps to ensure that the |
| colder temperature. | | | | greenhouse is tightly sealed during the night, too. |
| Now, you might be asking exactly what types of | | | | With this information on passive heating, you should |
| materials make for good heat sinks. Well, just to | | | | set to work and make Mother Nature proud! |
| make a few suggestions: | | | | |