By Gail Barnhill

The Tucson Watergardeners

Everyone seems to have their preferred method of potting up pond plants. While none are radically different, there are many subtle variations on the theme. This is my favorite:

The one thing you read over and over about potting medium for water plants, is that the soil should be very "lean" — in other words, not rich in organic matter. Just plain old "dirt" is dandy. If, however, you’ve worked for years on transforming your "dirt" into garden soil, it can be difficult to quickly come up with dirt for pond plantings. It also seems that most neighbors frown on you digging holes in their unimproved dirt…so what’s a water gardener to do? Well, I head to the market and buy the cheapest, unimproved, unscented kitty litter! Read the ingredient label to be sure it only contains clay.

Store kitty litter in a 5 gallon bucket with a lid to keep it dry. Besides the convenience of having a readily available source of planting media on hand, kitty litter is very easy to work with. It is easy to moisten quickly and evenly whereas dirt isn’t.

My favorite planter is the rigid black plastic "mesh" type. If I don’t have one available, a regular black nursery pot will do. If using the mesh type I line the entire thing with fiberglass screen material, letting the screen fold over the top edge of the container by an inch or so. For regular nursery pots I simply cover the drain holes with screen. You can also use coffee filters. They eventually disintegrate, but by then roots will keep the soil in the pots.

Begin filling the pot with kitty litter, being careful you don’t collapse the screen material. As soon as you’ve added about 3" of litter, moisten it well (but not "soaking"). I like to have about 90% of the litter wet, any more and your pot gets awfully heavy to lift! Continue adding/moistening until about 2" from the top of the container.

Next mix in some fertilizer. With a mesh container, be sure the fertilizer is deep in the center pot, as you don’t want it right against the sides and leaching into the pond. The fertilizer can be more widely spread in a nursery pot. I prefer the ease of using a time-release fertilizer rather than monthly plant tabs to feed my pond plants. I use one (Osmocote) that lasts for 9 months. There are other formulas that last 3 or 6 months as well. Push the litter back over the fertilizer and add more litter and moisten if needed.

Push aside the litter again as needed to insert the plant, and firm down the litter well, adding more if needed. Then add about 1- 2" of washed pea gravel on top of the litter, pushing it down slightly into the litter. Note that any water draining out of the pot will be "chalky" from the clay, but when placed in your pond this will quickly settle.

When putting a potted plant into a pond, tip the container slightly so that the pond water gently begins to fill the pot. If you submerge the pot "on the level", the pond water will "whoosh" over the top of the pot and disturb the soil much more.

Newly planted water plants with few leaves and short stems can be placed on top of bricks or another inverted pot to raise it closer to the water surface and sun. Once the leaves have grown and the stems elongated a bit, lower the pot either in graduated steps over several days, or all the way to the appropriate level.

Another, much appreciated benefit of using kitty litter, is that it’s MUCH easier to unpot overgrown plants. It doesn’t form as solid a mass as soil does.