Greenhouse Herb Gardening: Ventilation & Watering
One of the keys to successful greenhouse growing is proper ventilation. Proper ventilation in your greenhouse can solve some of your overheating problems and cool your greenhouse. Vents and fans in your greenhouse regulate the air temperature because they are constantly moving stale air out of your greenhouse while bringing in fresh air and moving this around your greenhouse. This will allow some of the excess heat to escape, and the fresh air will benefit your herbs.
Greenhouse herbs need a lot of fresh air because they become susceptible to pests and mold without it. Air can dry their wet leaves, preventing mold, and the steady stream of fresh air usually drives bugs away. Apart from installing vents or exhaust fans (usually best situated near the roof of your greenhouse, opposite its entrance) you should also install a circulation fan. Circulation fans make sure that all of your plants are getting a good amount of air going through and around them, which they need to stay healthy, create food for themselves through photosynthesis (the circulated air usually contains carbon dioxide), and pollinate (the circulating air will mimic natural winds.)
During the winter ventilating your greenhouse can become tricky. It is understandable that you don't want to ventilate it because you will be letting cool air in. Always remember that ventilation is a must in greenhouses, and while you will be letting cool air in, the air will help your plants. Maintain a temperature in your greenhouse through the insulating methods previously discussed, but never stop ventilation.
Watering
Many new time greenhouse owners tend to over water their plants because they are afraid that the plant will become too dry while in the greenhouse. This is a mistake. Over watering your plant in your greenhouse will actually lead to more problems than slightly under watering them.
If you are raising seedlings, use a misting method to water your plants. Electronic misting systems can be expensive, and a bottle with a spray nozzle should do just fine. Larger plants should be watered according to how you would water them if they were not in the greenhouse. In the case of herbs, watering them well one day and letting them dry out for a few days before watering again is the best method. Never water your plants until you can see that the soil around it is dry, and the first few inches of soil are dry. Constant water and moisture in a greenhouse can lead to soil mold even with the best ventilating systems.
Like a regular herb garden, water your greenhouse herbs in the morning, before the sun has completely risen. This will allow them to retain the moisture throughout the day and maintain just enough till the next time they have to be watered. If your plants have different watering requirements, take these into consideration, and follow the requirements for each plant. In this case, an individual watering method might have to be used. Watering globes can also be used in greenhouses, especially if plants are in containers, but soaker hoses, sprinklers, and shower watering are usually bad ideas for greenhouse herbs because they encourage mold.
