[Ebook Việt Hoá] Plant parenting – LESLIE F. HALLECK (Nhân giống cây) – HUMIDITY DOMES (Hộp giữ ẩm)

Managing temperature and humidity can be tricky inside a typical home that runs air conditioners and heaters. The low humidity in our homes can quickly dry out young plants or seeds as they are trying to germinate. Don’t have a greenhouse? No problem. By using a humidity dome on top of your seed trays, you can replicate greenhouse conditions on a smaller scale. You can purchase humidity domes separately to fit on plug trays or to cover other types of containers. There are also numerous mini-greenhouse kits available for purchase that come with everything you need to manage humidity for your young seedlings and rooted cuttings. 

Many humidity domes have top or side vents. After the seeds have germinated and begin growing or cuttings begin to root, you can open the vents to slowly reduce humidity. If too much water begins condensing inside the dome, or you keep the humidity dome on too long, fungal diseases or rot could set in. While young seedlings and cuttings do need to remain moist, too much moisture in the air around the seedlings can promote damping off disease, which causes seedlings or cuttings to rot at the soil line and topple. Too much humidity also encourages powdery mildew on young seedlings, cuttings, and transplants. You can remove  the humidity dome or other cover once all your seedlings have germinated or cuttings have rooted and begin to produce new green growth. 

You can also use a variety of other plastic con- tainers with clear covers. You know all those take-out containers that come with clear plastic lids or small vegetable containers from restaurants or the grocery store? I use them frequently as mini-seed-germination greenhouses. It’s a great way to recycle and reuse this type of plastic. 

If you don’t have a humidity dome or other type of plastic container, you can use clear plastic bags
to enclose pots or small trays of cuttings to increase humidity. Choose a clear, non-porous, plastic bag large enough to accommodate your container and cutting without compressing them. Set an individual pot, sev- eral pots, or small seed trays inside the bag. Blow some air into the bag to inflate it, and then use a twist tie to close the end of the bag. This method is good when you’re rooting individual or small groups of vegeta- tive cuttings. You can also use bell jars and terrarium covers to increase humidity around vegetative cuttings and seedlings.