Mulch contributes to bumper crop of tomatoes

I did an unscientific experiment by mulching heavily in one of my raised beds, which had a bountiful harvest; lightly mulching one-half of another bed, which had a better than ever but not so great harvest; and using no mulch on the other half, where barely any plants were producing when the heat hit. In fact, in the unmulched half-bed, the plants died off midsummer like they usually do.

My first question relates to the mulch. In the Pacific Northwest (Oregon), I would always clean up my beds by removing any leaves, etc. (because of pill bugs and slugs). Should I leave them as is because of our lack of bugs in the winter or should I till it under to enrich the soil?

My second question relates to the most disgusting bug I ever encountered. It was like a Stephen King nightmare. I found two of those horned tomato worms decimating my mulched tomatoes. Is it possible that there were eggs that came with the mulch? I quickly ran out and got some super killer that did work, but it was after the fact. My question is how to prevent them from even showing up again? Is there a preemergent I can use on my tomato plants when I first plant?

A: I am very happy to hear that you had luck this year with your tomatoes. Please let me know which varieties you planted and you liked. You can usually do quite well here with any of the cherry, grape or yellow pear tomatoes. Full-sized tomatoes are usually a bit more of a challenge.

Now regarding your mulch. You actually have two choices: Remove the mulch and, hopefully, compost it or till it into the soil, water and fertilize it and allow it to break down. If you till or incorporate your surface mulch into the planting beds, you will need to add some high-nitrogen fertilizer or compost along with the water to help break it down.

In either case, you should remove the mulch from the soil surface and allow any pests to be picked away at by birds and other predators.

Secondly, if you have enough room, you should be rotating your vegetables to different locations in the beds. All vegetables that are in the tomato family, such as tomatoes, peppers and eggplant, could be grown where you had squash or melons.

Tomato hornworms, that disgusting bug, worm or caterpillar that you refer to, arises from eggs laid by a large moth, not from the mulch. You can prevent that insect from becoming a problem by marking your calendar when you saw them this year. Next year, about two to three weeks prior to that date, you can spray an organic pesticide containing Bt on the plants. This should prevent them. You usually see them in the spring and fall months.

Q: I have a trailing jasmine on an east wall. It was planted six years ago and has grown to fill the entire wall. I know that it sheds leaves at this time of the year, but I do not remember it shedding as much as it has this year. I have a neighbor who has the same plant on an east wall and it has not lost that many leaves. I am exposed more as I do not have a house on the east side for a buffer.

Is there something I should be doing other than watering with drip irrigation three times a week (three waterings of seven minutes each)?

A: I am not sure how much water the plant is getting with seven minutes, but it is probably very little. It would be nice to know how many emitters the plant has and their size in gallons per hour. A plant that size needs between 10-20 gallons each week this time of the year. If you are giving it this much, then in midsummer you would water about three times a week.

This time of the year you should be able to water about once a week, but it will need much more water than what you are giving it. With the watering you are giving it, the roots will be very shallow. This also could lead to a loss of leaves.

Make sure the plant has mulch around it and start watering deeply so the roots will go deeper. Gradually water less often to help the roots follow the water to greater depths. Use a high-phosphorus fertilizer to help root development. You can use fertilizer stakes with a high middle number and put one under each emitter.

Q: I have a schefflera plant. I have had it for about nine years. It is now to my ceiling and still getting new leaves. There are three plants all the same size in one pot. One plant is getting three new leaves and the other two are getting two new leaves. It is so big and beautiful I hate to cut it, but it has no more room to grow. What can I do?

A: You really have no choice but to cut the schefflera, or umbrella tree, back.

There are two types of cuts that you can make. One is a heading cut, which is a cut that leaves a stub somewhere along a stem. Just beneath this cut, two or three buds should emerge to continue the growth. If the small stub dies back, remove it after strong and vigorous growth has occurred. This heading cut causes the canopy of the plant to become more dense because, for every cut made, two or three new shoots are created.

The second type of cut is a thinning cut. Thinning cuts, as the name suggests, usually results in a thinning of the canopy. This is a cut that removes an entire stem or branch back to its source.

Once the cut is made, the remaining branches will continue to grow. Selecting the tallest stems and removing them results in a smaller plant.

The cut stems can be used for propagating. If you try this, make sure you use a rooting hormone and keep the cutting out of sunlight and in a humid location until you see new growth.

It is very likely that these thinning cuts will result in some new growth below where the cut is made. Vary the height of your cuts so that you have new branches emerging at different heights. When you cut these stems, make sure that your pruning shears have been sterilized with alcohol and they are sharp.

Bob Morris is an associate professor with the University of Nevada Cooperative Extension. Direct gardening questions to the master gardener hot line at 257-5555 or contact Morris by e-mail at morrisr@unce.unr.edu.