How to Use an Old Rowboat for a Planter Box

Set the old rowboat in an area that receives sufficient sunlight for the kinds of plants you want to grow in the boat. For example, most vegetable plants require six or more hours of sunlight each day while shade-tolerant flowering plant may need only four hours of sunlight daily.

Remove all benches and other protrusions inside the boat. The boat should have an open cavity to fill and plant.

Drill 1-inch-diameter holes in the boat's bottom, placing the holes at 6-inch intervals in rows set 4 inches apart.

Fill the bottom 12 inches of the boat's depth with fist-size rocks. Cover the rocks with a layer of sand. The rocks are filler, taking up space that otherwise would be filled with a soilless potting mix.

Add a commercial soilless potting mix on top of the sand, using enough to reach within 4 inches of the boat's rim. Alternatively, make your own soilless potting mix by combining equal parts compost or manure, perlite and peat moss. Mix with either the commercial or homemade soilless potting mix 1 tablespoon of a balanced fertilizer, such as a 10-10-10 blend, for every 1 square foot of growing space within the boat.

Plant seedlings in the boat's potting mix. Space the plants at the distances recommended for their plant variety. A plant's spacing distance usually equals the plant's expected mature width. Plant seedlings that will become tall plants on the north side of the boat. In that location, they won't shade out shorter plants.

Water the potting mix in the boat immediately after planting. Use enough water to make the entire mix evenly moist. Check the potting mix's moisture level daily, and water the potting mix when its top 1 inch begins to dry. Applying a 2-inch-deep layer of mulch over the potting mix helps to slow drying by inhibiting evaporation.

Fertilize the plants every eight to 16 weeks while they grow actively. Apply 1 tablespoon of the balanced fertilizer to every 1 square foot of potting mix, sprinkling it on the potting mix around the plants. Water the potting mix so the sprinkled fertilizer soaks into it.

Water the plants at their soil level. Dry foliage minimizes the chance of diseases. Remove diseased plants immediately. Otherwise, the disease or diseases may spread to healthy plants.