The Dirt Gardener's Column for June 19

Q. My Zebra plant, Calathea is doing very well. It even bloomed last year. Now, it needs to be repotted as the leaves are starting to curl and water runs out of the container quickly. My quandary is that I don’t want to transplant it into a larger pot. The present container is fourteen inches wide. I've read that when a houseplant reaches the desired pot size, you can just change the top few inches of soil every year, leaving it in the same container. I'm not sure that would solve my problem though. I’d appreciate any suggestions?

A. Any plant that thrives in a container in doors or out will eventually become root or pot bound. There is a direct relationship between the vegetative portion of the plant and amount of roots necessary to support it. The roots take the place of the soil that is lost over time. When this occurs water penetration becomes difficult with water running out the bottom of the container quickly. Water stress occurs sooner causing the leaves to curl; hence, you’re watering more frequently. The suggestion to replace a couple of inches of soil is more like a band-aid than a permanent fix as the bottom half of the root ball is ignored. My solution would be to prune the root ball and replant it into the same container. This is done by removing the plant from the container, slicing two to four inches off the sides and three to six inches off the bottom of the root ball. You can use a knife or pruning saw. Next, you add fresh potting soil to the container and replant. Root pruning is a very simple task but one that gardeners are very nervous about attempting. They’re afraid of some type of catastrophic happening. Well, it’s successfully done all the time so just go for it.

Q. I planted a Fescue lawn from seed and it's germinating but it is a little spotty in certain places. Will the bare spots fill in?

A. Turf grasses are group into two broad categories, cool and warm season varieties. They’re further classified as spreading or rhizomes types and clumping. Bluegrass is a rhizome type of grass while Fescue is not. Tall and dwarf Fescues are the primary types used for lawns. Chewing and Red Fescue, which do produce rhizomes, are also available in seed mixes. They’re often added to help establish a lawn quicker. A detail list of the grass varieties are found on the packaging. Tall and dwarf Fescue fill in bare spots slowly. The new grass plants develop from the base of the existing mother plants. I wouldn’t wait for them to fill in instead; I’d re-seed the bare spots and any areas that seem to be thin. Bare spots develop from poor seed distribution or more than likely from the seed floating from water puddling during the germination period. I would try hand watering the new reseeded areas as you can control the water puddling.

by Buzz Bertolero, CCNP