Stepping stones

Q: We want to put in a path of stepping stones this spring, as soon as the ground thaws. Are there some rules about sizes and shapes, so that we will be happy with the result and not have to rebuild it next year?

A: There certainly are some good guidelines. Following them will avoid common mistakes like making a path so narrow that no one wants to use it. I like the look of stepping stones also, and I use them throughout my flower gardens. They make convenient platforms where I can work in the garden without compacting the soil where I stand and without accidentally tromping on flowers behind me. I also have paths of stepping stones to both the front and back doors. They never get mud or dust on my feet; they drain water quickly; and they are reasonably easy to maintain over the years. Most of all, stepping stones set in grass, flowers, or ground cover harmonize with a Montana landscape. They do not look like a misfit from a formal garden in Italy.

Having agreed on the desirability of stepping stones, how to proceed? First purchase stones or collect native ones. The cost of purchased stone is less if it is actually molded concrete. For walking along a path, the stones should be 12 inches wide. If a stone is to be a platform for standing, 2 feet is better. If the stone path becomes a landing outside a door, 3 feet is necessary. Of course the wider stones need not be a single slab. Two or more stones can be placed side by side with a narrow gap to accommodate temperature changes.

Always err on the side of too wide a path. We all tend to underestimate the minimum required for comfort. For instance, a front walk should be planned at least 4 feet wide. That is the width of my front path, which I built with a lucky guess before I had read any of the guidelines. It is wide enough to look welcoming, wide enough to let two people approach side by side. No path ends up being as wide as it was planned because plants on each side fall over the edges.

A path that will be used with a garden cart or a lawn mower also needs to be 4 feet wide. Wherever a path is near a building, it should be at least 30 inches from the wall; otherwise, walkers will find their shoulders bumping the wall.

Use a variety of shapes and sizes of stone if you do not want a formal effect. When buying concrete pavers for a walk, select at least three different ones. It is possible to find native stones suitable for a walkway, but the search takes time. Every stone must have a flat side, and most of the ones scattered across the landscape will not. The job also requires many trips between the source and home. Rocks are heavy.

I also have made stepping stones from pieces of an old sidewalk, broken apart with a sledgehammer and cold chisel. The irregular edges soften the look of concrete and make it into a pleasant path.

To create the path, lay out and rearrange the stepping stones until their position looks good. Then, to check the spacing, walk the path a few times, starting from both ends. That will ensure that each stone is where a foot will naturally fall. Install the path by digging out the soil under each stone. Remove enough dirt so that the top of the stone is about 2 inches above the soil level. This is an easy job with flat bottomed concrete pavers; with native stone, which is not flat on both sides, it takes a lot of fiddling to shape the hole. If the stepping stone path will get a lot of traffic, it is recommended that a base be dug out for each stone, 2-to-4-inches deep, and filled with gravel.

Finally, stand on each stone, shifting your weight from one foot to the other and moving dirt as necessary until the stone does not rock. When all the stones are solid, I like to pour a little sand around the edges to fill up any unseen holes. Grass or plants will soon grow to soften the outlines.

Q: This is the time of year when I always start to worry about flowers blooming too early. I am afraid that our unpredictable spring weather will produce a cold spell that kills the flowers. Do you cover tulips after the first leaves appear?

A: No, not tulips, crocuses or primroses. It is theoretically possible to grow a plant so far from its native habitat that its flowers would always appear too early and die of cold, but it is unlikely. Flowers that are hardy enough to live here usually do not bloom until the weather is warm enough.

I was fascinated to learn recently how the flowers protect themselves. Their genes include one called Flowering Locus C, usually abbreviated as FLC. It prevents a plant from flowering. The plant also has a protein that gradually deactivates the FLC gene as the weather warms in the spring. When the FLC gene is completely turned off, the plant can bloom. Without that bit of protein to suppress the FLC gene, the plant would never flower. And we think that plants are simple organisms?

When early-flowering bushes like forsythia do not bloom some years, the cause is different. The flower buds had formed the previous summer and were killed by a cold spell in the fall. They did not survive into winter, much less all the way through it.

Q: I can grow tomatoes that turn red on the plant. The problem is that they don't taste very good. Is there anything that I can do this summer to make them taste better?

A: Two things should give you better tasting tomatoes. The first is to keep track of the early tomatoes that you grow. Never plant again the ones that were sour; that is an unfortunate characteristic of some early varieties. Seed descriptions for kinds you want will mention flavor. If you buy plants, ask at the nursery for the best tasting early varieties.

Do not worry whether you have the very earliest kind. If a tomato ripens in less than 70 days, it should ripen for you. If your garden is at high altitude, grow cherry tomatoes or other small ones. They are the fastest to ripen.

The second trick is to pick each tomato when it is more pink than green and let it finish ripening in the house. It will taste the same as one that turned completely red on the plant. As soon as it is picked, the plant will begin ripening the next tomato, and you will have more ripe tomatoes, sooner.