Ponds need plants for a number of reasons. Floating plants, with their broad leaves, shade the water and prevent it from becoming too warm. Fish fry hide among the trailing roots of plants like water hyacinth and water lettuce. The flowers of water lilies add color to the surface of the pond. Underwater plants have a less colorful but just as important job. They add oxygen to the water and remove impurities and ammonia, keeping the water healthy.
Choose the oxygenating plants you prefer. One of the most popular is anacharis, with its long swaying stems and short leaves. Red hygrophila has red broad leaves. Jungle vallisneria has long ribbon-like leaves that flow with the water currents.
Determine how many plants you will need, based on the size of your pond. A smaller pool of 3 by 4 feet requires nine bunches. A bunch has three to five plants. A medium-sized pond needs 20 bunches and a large pond, up to 10 by 15 feet, requires 60 bunches.
Fill a water plant basket, or terra cotta pot, to within 4 inches of the brim with top soil that does not contain vermiculite or perlite (those will float to the surface and ruin the look of the pond). Top soil is different than potting soil. Check the label when you purchase it.
Gather the oxygenating plants with the growing tips pointed up and roots down. Some plants don't have roots. Place the roots, or the opposite ends from the growing tips, into the pot. Cover with soil.
Cover the soil with pebbles to weight the soil down. Place the plant in a bucket of water. Fill the bucket with water until the top of the pebbles is covered with a few inches of water. Let the soil absorb the water for 15 minutes. It will bubble as air escapes from the soil
Remove the pot from the bucket and place on the bottom of the pond.