If you are just using them to start things from seeds, you can use regualr shop lights- Floresent. the long tube kind. Then you just put it 2 or so inches above the plant and keep it on for 16 hours a day. It will not give enough light to acutally grow the vegtables, but it starts the seedlings off just fine. Be sure to use ones that have guards going on the sides to make them wider to direct the light better. but other than that they dont have to be special.
Have you added peat moss to your garden? Also I like to use milk cartons put deep in the soil with holes in them and I just stick the hose in the top, and the water soaks out that way. It has been very effective for me. My garden was amazing last year watering the big plants that way. It would not work for root plants, but most other ones it works great. Than it dosnt get a chance to sit on top, and less weeds beacuse the top stays dry.
Hope that helps.
"Thanks Charlotte and Lorraine. These astilbes and ferns are against the north side of the house, so they are in shade most of the day. Lorraine, you're right that astilbes (and ferns) will scorch if they get too much hot sun."