tomato blossom end rot

CORVALLIS, Ore. – For most gardeners it’s been a normal or above-average year for the country’s most popular vegetable.

“It was a fairly decent season for tomatoes,” said Brooke Edmunds, horticulturist with Oregon State University Extension Service. “We got warm enough and didn’t have any early cold spells. If you were irrigating, you probably had a pretty good year.”

Some things – like weather – you can’t control. Tomatoes, which are actually a fruit, thrive at ambient temperatures between 65 and 85 degrees and this year we had plenty of days in that range. Some things you can control, like how much you water and how you treat the soil.

If you had problems with blossom-end rot this year, take stock of the soil pH and review your watering practices. Blossom end rot shows up in many cultivars when calcium in the plant is low. Calcium uptake by plants is affected by several things, including low soil pH and water availability. The best way to adjust a low soil pH is to add lime to the soil in fall. In Extension’s publication Blossom-End Rot in Tomatoes instructions say to use lime to adjust the pH of the soil to 6.8 to 7.2 in order to aid the plant in taking up calcium. Many Willamette Valley garden soils benefit from at least 5 pounds of lime to 100 square feet every three years. Mix the lime thoroughly into the top 8 to 12 inches of soil in fall.

When it comes to watering, tomatoes don’t respond well to extreme dry-wet cycles, so water regularly when soil is drying out, Edmunds said. And remember, tomatoes want well-drained soil.

Blights can show up, also, and are more difficult to fight. Edmunds said the best method is to give tomatoes good air circulation by keeping them staked up and pinching off suckers (the branches that grow at the joints) that can shade the fruit. Pick out affected leaves and put them in the garbage rather than composting. Avoid overhead watering. Instead, use drip irrigation, Edmunds recommends. If possible, move plants to a different site year to year, coming back to the original spot on a three-year rotation. For more information on blight, see Pacific Northwest Pest Management Handbooks.

In areas with shorter seasons like much of Oregon, it’s a good idea to choose early-ripening varieties, Edmunds said. Some bred by OSU include:

  • Legend: A tomato that produces large fruit that is good to eat straight off the vine. Resistant to some forms of late blight. Ripens 60-65 days after transplanting. You can get a larger-sized, earlier-ripening fruit by growing them first from seeds in gallon-size pots then transplanting them.
  • Gold Nugget: Among the first to ripen, this prolific variety grows cherry tomatoes with a deep yellow color and mild, juicy flavor. Ripens in 60 days.
  • Oroma: This tomato makes good tomato sauce and paste. Early to mature; average ripening time of 70 days. Prolific after ripening. Fruit is meaty and thick-walled.
  • Oregon Spring: Ripens in 60-70 days. Slicing variety that can be eaten fresh in salads or straight from the vine. It will produce high, early yields of silver-dollar-sized juicy tomatoes. 
  • Oregon Star: Ripens in 80 days. An early-maturing, red paste-type tomato. Large, seedless fruit. Good for fresh eating and for canning.
  • Santiam: Ripens in 65-75 days. Suited for salads and fresh eating; good, tart flavor. 
  • Siletz: Ripens in 70-75 days. Reliable tomato with good flavor; ideal for eating fresh from the vine. Not resistant to late blight.
  • Indigo Rose: Ripens about 80-90 days after transplanting. First of a new class of tomato that is high in antioxidants. Its purple color comes from the anthocyanin pigment in its fruit. This open-pollinated variety is a prolific producer. Get the best flavor by picking the tomato at its ripest; it will turn a muddy brown, dull purple color in September when ripe.

Another great resource for finding the best tomato varieties is Vegetable Variety Trials, 2017, which includes lists of vegetables grown and evaluated by OSU Extension Master Gardeners led by Edmunds. Tomatoes are ranked from 1 to 9 in such categories as fruit size, color and taste, how many days to maturity, and yield. The evaluation also includes cabbage, pepper, pumpkin and ornamental gourd and winter squash.

Find tomatoes from both lists in the seed catalogs from Territorial Seed Co., Victory Seed Co., Ed Hume Seeds, Johnny's Selected Seeds, Nichols Garden Nursery and others. Many varieties will be available as starts at garden centers.

 For more information, refer to Extension’s Grow Your Own Tomatoes and Tomatillos.

If you want to save your own seed, remember that hybrid varieties won’t come true to type, while open-pollinated and heirloom ones will. The seed packet should tell you what type tomato you’ve chosen or check the internet.

Saving seed can be a little messy, Edmunds said. Cut open the tomato and squeeze out the seeds, which will be coated with a gel-like substance. There are different methods for removing the gel, but the easiest is to put the seeds in a mason jar and add two-thirds water by volume (one-third seeds, two-thirds water). Stir it up and leave it to ferment. Mold will grow on it and break down the gel, seeds get released and sink to the bottom. Pour them out into a sieve or small colander and wash them off. Spread on a paper towel to dry, which could take one to two weeks. Then package them up in envelopes or jars (don’t seal all the way).

No matter what you do, there’s bound to be green tomatoes left on the vine. Edmunds notes it’s possible to ripen those with a little color by laying them out in a single layer in a dark area, like a loosely closed box in a closet.

“Some cultivars do better than others,” she said. “It’s fun to try.”

Barring that, why not use your green tomatoes and not just fried?  Jeanne Brandt, a family and community health expert with Oregon State University Extension Service, offers two recipes. One is her favorite salsa, which is called Tomatillo Salsa, but the recipe is just as good with green tomatoes. It’s in Salsa Recipes for Canning on Page 6.

The other is for Pickled Dill Tomatoes. “Some people love them, especially when they substitute hot peppers for the green peppers, which is fine to do. You can use a mixture of green and partially ripe yellow tomatoes for interesting colors.

 

Extension Service

About the OSU Extension Service: The Oregon State University Extension Service shares research-based knowledge with people and communities in Oregon’s 36 counties. OSU Extension addresses issues that matter to urban and rural Oregonians. OSU Extension’s partnerships and programs contribute to a healthy, prosperous and sustainable future for Oregon.

Story By: 

Kym Pokorny, 541-737-3380, [email protected]

Source: 

Brooke Edmunds, 541-730-3470, [email protected]

 

 
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