Looking Ahead to Tomato Season

Tomato variety Rose of Berne

Tomato variety Rose of Berne

The second week of June is tomato planting time in Marjorie’s Garden.  At present, seven days into May, week-old tomato seedlings grow under fluorescent lights in a warm room.  It will be another week before we transplant the seedlings to individual pots and the first of June before those transplants are hardened for the garden.  Whether home-grown or purchased from a greenhouse grower, tomato transplants need gradual acclimation to the full sunlight and wind that they will experience in the garden.

We use our sunny porch railings and steps for this acclimation task.  On the first day, in the morning, we move the seedlings to the porch and give them an hour of angled light as well as exposure to wind.  If the wind is hard and constant, we either delay hardening for a day or place the plants where the wind is buffered.  Each day we extend this outside time by an hour, so that by the end of the week the plants are ready to be planted in the garden.

In the garden, the bed has already been prepared, the soil amended with aged compost.  On planting day, at the bottom of each hand-dug hole, I add two handfuls of worm compost, an extra dose of slow-release nitrogen for the growing plant.

Transplanted tomato seedlings should be fitted with a cutworm collar made from rolled newspaper.

Transplanted tomato seedlings should be fitted with a cutworm collar made from rolled newspaper.

I make each hole deep enough to set the transplant a few inches deeper than it was growing in the pot.  New roots will form along the buried portion of the stem, and the plant will be better anchored in the soil and less likely to bend or break in stiff winds.  Before completely backfilling the hole, I wrap a newspaper cutworm collar around the stem so that it is an inch below and above the soil line after the hole is filled.

If you have purchased greenhouse-grown plants in plastic pots, you may have to deal with a mat of circling roots surrounding the soil, a sign that the plant has been in the pot for too long and become “potbound,” a condition that will limit its vigor after planting.  Gently pull the circling roots  away from the soil ball with your fingers, spreading them outward.  Circling roots at the bottom of the pot should also be pulled loose and spread out before planting.  Even cutting away this bottom root layer is preferable to leaving it intact.  If you purchase plants in fiber (peat) pots, tear the pot completely off the plant before planting.

The Tomato Grower’s Dilemma: Cage or Stake?

Cages made of of concrete reinforcement mesh can be used to support tomatoes.

Cages made of of concrete reinforcement mesh can be used to support tomatoes.

Tomato plants must by supported off the ground, particularly where slugs are part of the food web.  Upright plants take up less garden space and the enhanced air circulation reduces foliar and fruit disease.

Which method of support, stakes or cages, is best?  While both have their merits, I recommend cages for two reasons: less maintenance (minimal pruning), more (if slightly smaller) tomatoes, and less sunscald.

Staked tomatoes require extensive pruning, the removal of lateral or side shoots that appear in the leaf axils between the stem and the leaves.  If not removed, these shoots compete directly with the main stem, weakening it, and strong side shoots loaded down with fruits can easily break their attachment to the main stem.  Removal of the side shoots also reduces foliage cover, increasing the chances of fruit sunscald.

Cages made of concrete reinforcement mesh an be used to support tomatoes in pots.

Cages made of concrete reinforcement mesh an be used to support tomatoes in pots.

Caged tomatoes do not require removal of all lateral shoots.  The fruit-bearing side shoots are supported by the cage wire while the abundant foliage cover protects the fruit from sunscald injury.  The heavier fruit load will delay ripening a bit and result in somewhat smaller fruits.

To minimize foliar diseases such as fungal blights, I do recommend removal of lateral shoots below the fruiting zone of the plant, whether staked or caged.  Wait until the first flower buds are formed, then remove all of the side shoots below them.  Do not do this before flowering, however, when the plant needs all of its leaves for maximum photosynthesis.

Staked tomatoes with lower branches removed.  When flowering begins, prune off all side branches below the lowest flowers.

Staked tomatoes with lower branches removed. When flowering begins, prune off all side branches below the lowest flowers.

If you decide to go with cages, build your own out of concrete reinforcement mesh.  The openings are wide enough (six inches) for your hand to reach in and harvest tomatoes with ease.  And they will last forever.  Other tomato cages are flimsy by comparison.

A cage five feet tall will support most tomato varieties.  A five-foot length of five-foot-wide mesh can be rolled into a cylindrical cage with an 18-inch diameter.  A six-foot length will produce a 21-inch diameter.  Form the cylinder by hooking the two cut ends of the mesh together, then remove the bottom rung to form prongs to push into the soil.  For stability, tie the cage to a strong stake driven into the ground.

With a little practice and a bolt cutter, you can make a cage in about fifteen minutes.  Don’t be surprised if the comes with an exterior layer of rust, the result of storage outside at the builder’s supply store.  The tomatoes won’t mind.

Flowers But No Fruits

One of the most frequent questions I receive from readers goes something like this: “I have plenty of flowers on my tomato plants, but no tomatoes.  What’s wrong?”  Really observant gardeners may note that the flower stems turn yellow just before the flowers drop to the ground.

The diagnosis is not easy, since there are several possible causes of blossom drop in tomatoes.  It is often the result of extreme temperatures during the day or night.  Development of the pollen tube, a post-pollination event essential to fruit development that must occur within 24 hours of pollination, is inhibited in many tomato varieties by daytime temperatures above 85 degrees, night-time temperatures above 70, and, most often, night-time temperatures below 55. The later is a possibility in any summer month for northern New England.

Also, if nighttime temperatures are less than 55 or greater than 75, or daytime temperatures are greater than 85, recently deposited pollen may become tacky and non-viable.  Fruits that do develop are more likely to be misshapen or cat-faced when night temperatures are below 55.

These temperature-related causes of poor fruit set can be minimized by selection of tomato varieties that are suited to cool summers.  When perusing seed catalogs or shopping at the local garden center, choose varieties with the shortest number of days to maturity, an indication of suitability for gardens with cool, short summers.  But don’t believe the actual number, as ripening will happen more slowly in a cool summer.

Blossom drop may result from lack of pollination, the transfer of pollen from the male part of the flower (the anther) to the female part (the stigma).  Tomatoes flowers must be vibrated or shaken for this transfer to occur and this is normally done by wind or bumblebees.  If both are lacking in the garden, frequent gently shaking of the flowers by hand may work to improve  pollination.

Other cultural causes of blossom drop include nitrogen levels that are too high or too low.  Given too much nitrogen, the plant diverts most of its energy to vegetative growth; given too little, it may be too spindly and weak to sustain many developing fruits.

Lack of water will also lead to blossom drop.  Tomato plants have deep roots, some as deep as five feet.  Shallow watering stresses and weakens plants.  Tomatoes respond best to deep irrigation once each week, unless the garden gets a soaking rain.

Don’t Miss This Spring Plant Sale!

Hancock County Cooperative Extension Master Gardener Volunteer Program

SPRING PLANT SALE

Saturday, May 16, from 8 am to noon (rain or shine).

LOCATION: 63 Boggy Brook Road, Ellsworth, Maine.

Hundreds of your favorite perennials, including Maine natives.

SCHEDULED TALKS:

    “Native Plants for the Landscape” by Reeser Manley, at 9:00 am
    “Moss Gardening” by Jan McIntyre and Claire Daniel, at 10:00 am
    “Vermiculture” by David Struck and Lavon Bartel, at 10:30 am
    “Backyard Composting” by Tom McIntyre and Gaylord Sundt, ongoing
    “Ask a Master Gardener” table, all morning

Book Signing (all morning): THE NEW ENGLAND GARDENER’S YEAR, by Reeser Manley and Marjorie Peronto

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About Reeser Manley

I was born in Laramie Wyoming but moved to the southeast at an early age. I was educated through my B.S. in Biology in the Columbus, Georgia area, then crossed the Chattahoochee River to earn my M.S. in Botany at Auburn University. For the next ten years, I worked as Horticultural Manager for the George W. Park Seed Co. in Greenwood, S.C. At 40 years of age, I decided to return to graduate school and in 1994, I earned a Ph.D. in Horticultural Science from Washington State University, Pullman, Washington. Fast forward through 10 years at university (7 at UMaine, Orono) and you find me teaching high school science in Eastport, Maine, the edge of the world, and writing a weekly garden column for the Bangor Daily News. My new book, The New England Gardener's Year, a Month-by-Month Guide for Maine, New Hampshire, Vermont, Massachusetts, Rhode Island, Connecticut, and Upstate New York”, will be published later this year by Cadent Publishing. You can learn more about the book by visiting its Facebook page: http://www.facebook.com/pages/The-New-England-Gardeners-Year/187285218055676.)