If you've run out of room for a garden, or perhaps just want to try your green thumb growing a few vegetables, expand your gardening space using potting soil still in the bag. Get a jump start on warm season vegetables by warming up the soil in the bag. Start seedlings to transplant into your garden. Try a few varieties of plants you're not quite sure about. You won't even need extra pots; the bag is the container.
Place the bag of potting soil measuring 3 cubic feet where you intend the plants to grow. For sun-loving plants, it should be where it receives 8 hours of sunlight a day. Place bags for shade-loving plants in the shade.
Put the bag of potting soil in the garbage bag. Lay it horizontally on the ground. Stab the bag and garbage bag once on each end to make drainage holes. The dark garbage bag heats up the soil, allowing you to plant earlier in the season.
Place a hose in one of the drainage holes. Let the water run into the bag to moisten the potting soil. It should be thoroughly wet. You may have to put the hose in holes on both ends of the bag to reach all the soil.
Roll the bag over so the drainage holes are on the bottom. Press on the bag so the soil is evenly distributed.
Cut an "X" through both the garbage bag and potting soil bag. The "X" should only be big enough to allow the root ball of the plants to slip in.
Pull back the flaps of the "X" and put the plant in the soil, completely covering the root ball. Small plants like marigolds, strawberries or beans should be 6 inches apart. Plant larger plants like zinnias or peppers 12 inches apart. Plant two large plants like tomatoes in one large (at least 2 cubic feet) bag of soil.
Use a smaller bag of potting soil, such as 1 cubic foot, for medium plants like roses or a 12-quart bag for smaller individual plants.
Place the bag in its final position. It will be heavy to move after it's filled with water.
Stab the bottom of the bag to make drainage holes.
Turn the bag so it is right side up. Cut the top open and remove some of the soil. Push the bag down against the ground so it presses the bottom of the bag and becomes more stable. You may have to remove more soil so there's room in the bag.
Plant the rose bush or other plant in the bag, covering its root ball completely.