Seed Pots
Start your seeds in yogurt cups, plastic take out containers, used party cups, toilet paper rolls, egg cartons, egg shell halves or seed pots fashioned out of newspaper. Keep any containers from new plants, and use them to start next year's seeds.Mini Greenhouses and Cloches
Protect young plants from the elements with items from your recycling bin. Milk jugs make great mini greenhouses. Just cut them open a few inches from the bottom to create a tray for planting; then, use the top of the jug as a cover when temperatures dip. Clear plastic fast food cups with lids also work well as mini greenhouses, as do used plastic sandwich bags (just slip them over top of pots that you want to protect).
Need cloches for your new transplants? Cut the tops off of soda bottles; remove the caps; and place them over your plants. the globes from old light fixtures work well, too.
Fertilizer
Calcium-rich egg shells make an excellent fertilizer for tomatoes. Acid-loving plants like roses, blueberries and azaleas are fond of coffee grounds, and nearly any plant will thank you for a splash of nitrogen-rich fish tank water. Look around your house, and you'll start seeing free fertilizer everywhere.
Weed Barrier
Lay down a thick layer of newspaper before you mulch to keep weeds from coming up. It works just as well as landscape fabric, and it's biodegradable.
Flower Pots
Reinvent old boots, wooden crates, coffee cans and other household objects as fun and frugal flower pots. Veering away from store-bought containers gives you an opportunity to inject your own sense of style into your garden.
Pot Filler
Save broken flower pots, and use the shards to cover the drainage hole in pots (this will allow the water to get out, but help to keep the soil in). Use balled up grocery bags or packing peanuts at the bottom of large pots to minimize the amount of soil that you have to use (and to keep the weight of your pots down).
Mulch
Use pine needles, pine cones, leaves or grass clippings in place of store-bought bark mulch to keep moisture in, weeds out and more money in your pocket.
Plant Markers
Transform used plastic spoons and can lids into plant markers; cut tags out of plastic milk jugs, or cut up old mini blinds for a lifetime supply of markers.
Tip: If you decide to make plant markers out of can lids, use a can opener that leaves the sharp edge on the can, instead of the lid.
Stakes, Arbors, Trellises and Cages
Fashion stakes, arbors and trellises out of sticks, old screen doors, headboards and whatever else you have collecting dust in the garage. Use pantyhose, twist ties and plastic bags to attach plants to supports.Seed Tape
Make planting easier without paying extra for seed tape. You can fashion your own out of newspaper:

