1. Get enough sunlight.
If a seed does not get enough sun the soil will not warm up and the seed may take a long time to germinate, if at all. This can be very frustrating. If a plant does not get enough light it will have tall, spindly growth and be more pale yellow. Plants do not do well with incandescent lights. They do not supply enough intensity. Fluorescents are used for indoor gardens. Plants need both blue and red light. You can use Fluorescents with an incandescent to help plants get both. Many purchase a light kit for their classrooms. I like to make a light hut. I use a 13-watt fluorescent and have had great results. Learn how to make a light hut. My seeds germinate very quickly and I get good growth with the plants. You may have enough windows, but do they face the right direction. South and west facing windows are best. Plants do need 14-16 hours of light a day. It is recommended they be within 12 inches of the light source. Sometimes that dries them out. Test and see.
When I taught in two different buildings I learned a lot about the importance of warmth. One building only had one window, but the classrooms stayed warmer. Seeds germinated well. The other building had a wall of windows. I thought it would work great. The rooms lost all their heat at night and the seeds did not germinate well or at all. To solve that problem I bought heat mats since the plants had enough sun. They are inexpensive and worked well. The light hut will also provide light and heat to help seeds germinate. The light hut is covered with foil. This allows light to reflect back onto the soil. Water the plants with warm water, not cold.
3. Use the right container and create drainage.
I like to use small yogurt containers, plastic cups, or black plant containers. You need to create holes at the bottom. To do this I take a thumb tack or needle and heat it in a candle flame. The needle will poke right through the plastic. I make about 5 -6 holes. They are the right size to allow some water to drip out. It is also a good idea to place some gravel in the bottom to help with drainage. If you get pour drainage your plants may get mildew or moldy. Noone wants moldy, un-sprouted seeds.
4. Make sure they get the right amount of humidity and water.
Set up a careful watering schedule. You may need to spray water on them to keep them moist. The lights can be very drying. I will often plant my seeds and add a little bit of water. I place plastic wrap over the top. It creates a greenhouse. I will keep the plastic wrap on until the seeds sprout. No need to water. Once they have sprouted I remove the plastic wrap and start a watering schedule.
5. Use good soil.
Plants under lights grow fast and need more nutrients to grow. I have used peat moss with good results, but not under my light hut. The light hut provides light 24 hours a day. Peat moss will dry out too quickly. I like using a good potting soil. Peat moss is fantastic when you are placing plastic wrap over the top of the container for sprouting. If you are using a good soil you shouldn't have to fertilize for the length of time you grow plants in the classroom. If you are growing them longer than two weeks the students may want to try adding some plant food.
Don't' be afraid to try growing plants in the classroom. Whether they grow well or not it will be a learning experience. Each year will be different, but you have to start somewhere. I wouldn't spend a lot of money on expensive plant garden products. You should be able to use these tips and have success. You may want to place the plants on a movable cart. That way if the spot doesn't seem to work you can move them to the best sunlight and warmth.
This plant bundle will guide the teacher and students to discover the best way to grow plants.