If you water lawns after sunset instead of in the morning or afternoon your savings in water because of less evaporation can reach 50%.

Mix 1 gallon of distilled vinegar, 1 cup of salt and 1 tablespoon of liquid dish soap
Spray weeds as they emerge and be careful not to spray on plants you want to keep.

If you grow tomatoes in a greenhouse white fly and black fly etc could plague you. Try growing African Marigolds between each plant, and a few for good luck, as apparently they do not like the fragrance, which tends to deter them.

Insufficient light is one of the major reasons African Violets do not bloom well. Violets must have 10 to 14 (16 is max) hours of bright light per day (no direct sun). Variegated varieties usually need more light than the plants with solid green leaves because there is less chlorophyll which is used to turn light into food for the plant. The special yellow blooming violet varieties need less light than all the other violets require. You can enhance the light for certain violets by sitting them on mirror tiles as large or larger than the violet. This reflects the available light back to the violet. If adequate natural light is not available or desired, twin tube fluorescent lights are ideal. Place the tubes eight to ten inches above the foliage for mature standard plants, and six to eight inches for miniatures, leaves, and seedlings. Because violets process nutrients during the "resting phase" (i.e. darkness) they should also have 8 hours of darkness per day.