The Road to Healthy, Productive Tomatoes

comments (11) August 5th, 2008

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Smokers, beware!
A number of tomato diseases can be transmitted on peoples’ hands or tools. None is more serious than a virus that is common on tobacco and thus on the hands of smokers, tobacco mosaic virus. Be sure that smokers who visit the garden wash their hands thoroughly before touching plants.

Since tools can easily move diseases from one plant to another, and wounds are common pathogen entry points, snap off tomato plant suckers cleanly by hand. Suckers are the new little sprouts that start up between the branches and the main stem.

Prune for aeration and don’t crowd plants. Learn to prune tomato plants for maximum aeration, yet adequate sun protection for the fruit. Start by leaving enough space between the plants, depending on the variety. Usually 2 ft. to 2-1⁄2 ft. apart is desirable. Then, once you have the main stem growing upward, snap off any suckers that start at the base. 

  See pruning in action:

Video: How to Prune Tomatoes
Encourage as much airflow at ground level as possible. Use trellises or tomato frames to support plants. Fruit touching the ground or heavy branches dragging in the dirt are highly susceptible to disease problems. Keep thinning plants as they grow to facilitate air flow into the center of the plant and ease harvesting. However, be sure to leave enough foliage to protect fruits from sunburn. Most importantly, moisture encourages the spread of disease, so don’t handle the foliage while it is wet.

Good nutrition and balanced watering promote healthy plants.
A number of tomato problems are actually responses to adverse environmental conditions. These stressful conditions can be reduced or avoided by using good fertilizing and watering practices. Strive for a neutral soil with a pH of around 7. Use a sprinkling of dolomitic lime to neutralize soil acidity before you plant your tomatoes and a fertilizer mix that is higher in potassium than in nitrogen. Digging in aged compost along with some bone meal, which is naturally high in potassium, should be all you need to meet these requirements. Keep in mind that too much nitrogen can trigger insect problems and encourage disease, in addition to producing a huge plant with more foliage than fruit.

Finally, water as evenly as possible. This is critical to avoid problems with blossom-end rot, a condition to which pear-shaped canning tomatoes like ‘Roma’ are particularly susceptible. Keep your tomato beds evenly covered with a deep compost mulch. Periodically pull back the mulch and check with your fingers to make sure the soil is moist all across the bed. If possible, avoid overhead watering. If you irrigate, add water from below, either with furrows or by using drip lines. On the other hand, if you garden in a high rainfall area, then raise the planting beds above walkway height to ensure adequate drainage. Compacted, poorly drained soils can cause as many problems as unevenly watered ones.

There are at least 35 diseases of tomatoes common in the United States. One excellent reference, Tomato Diseases: A Practical Guide for Seedsmen, Growers, and Agricultural Advisors by John C. Watterson, is now out of print, but you'll find many good sources online.

by William Olkowski
August 1997
from issue #10

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posted in: tomatoes, pests

Comments (11)

steviestever writes: Spraying a light iodine solution 2% has been very effective for me. It seems to give the plants some immunity boost and keeps the leaves green and strong. I've used garden sulphur but it's not half as effective or as pleasant to work with as the iodine. :)
Posted: 11:54 pm on August 9th
butchfomby writes: A lot of tomato problems i think are caused by plant not getting the calcium it needs...I had trouble with blossom end rot until I started adding a handful of epsom salts to each tomato...must be that epsom salts makes calcium available to the plant or so it seems...a good ratio of calcium and magnesium is vital also...also we add a handful of gypsum to supply calcium and not change ph...

I think tomatoes growing to fast causes a lot of problems...the best crop for me ever was very slow growing...seems like they would never grow and produce, but canned 300 quarts from 12 plants...never been able to match that season since...well water 240 ft deep, soil was sandy loam and filled in holes with virgin forest soil so had mycorrhizae going good, never got over 95 that summer...all you can do is keep trying...the indian
Posted: 1:48 am on September 16th
butchfomby writes: A lot of tomato problems i think are caused by plant not getting the calcium it needs...I had trouble with blossom end rot until I started adding a handful of epsom salts to each tomato...must be that epsom salts makes calcium available to the plant or so it seems...a good ratio of calcium and magnesium is vital also...also we add a handful of gypsum to supply calcium and not change ph...

I think tomatoes growing to fast causes a lot of problems...the best crop for me ever was very slow growing...seems like they would never grow and produce, but canned 300 quarts from 12 plants...never been able to match that season since...well water 240 ft deep, soil was sandy loam and filled in holes with virgin forest soil so had mycorrhizae going good, never got over 95 that summer...all you can do is keep trying...the indian
Posted: 1:47 am on September 16th
grimey writes:
I've been growing tomatoes on the damp West Coast of BC for many years and only avioded blight by 1)Cover them to keep all moisture, including night-time dew, off the leaves.
And 2) If you can't cover them, spray with copper sulphate every couple of weeks or after a rain. Copper sulphate spray is still considered organic practice.
And HaveGreenThumb is dead-on stessing the importance of calcium to prevent blossom end-rot. We save all egg shells, powder them in the blender, then throw at least 1 cup in every hole when we plant. In this form the shells break down for use by the plant...otherwise larger pieces remain intact and the calcium can't be used by the plant.
Posted: 11:27 am on July 9th
luckysea13 writes: I've a small garden space. I've grown tomatoes every year, in a difference spot in the garden. I don't have any problems w/ diseases or fungis & leaf blight. I get my seed from Big Lots or the Dollar Tree. I've not a single problem at all. Then, I've had those big green ugly worms w/ horns in the front. All I did was spray my tomatoes w/ a homemade organic insecticide to take care of the worms. Thanks for a good article on tomatoes & what to look out for.
Posted: 4:51 pm on July 13th
GardenShooter writes: Hello. In response to the numerous inquiries regarding tomato blight, spraying the soil in the garden with Neem oil in early spring, before planting, worked liked a charm in our garden. It also took care of squash bugs, something we'd been plagued with the prior season. After treating the soil with neem oil, we waited a week or two and then began planting. We had the most productive year ever after that.
Posted: 8:32 am on June 6th
mrgardenboy writes: To DMC58 & Gingercats

I had the same proplem with my tomatoes Last year I moved mine and switched them with my pepper plants and it seemed to work better.Also a home remide trick here in southern Michigan we get our frost Early October or Late September And I start getting the same proplem you are getting ut off the leaves that are bad this takes away food from the good part of the plant.I use TARGET OR MEIJER BRAND Mouthwash The mouthwash keeps the bugs off try getting a strong one it does not matter if it is expired.This will keep the bugs and the leaves from turning yellow or white spots.If this does not work you may need to find another location for your tomato plants.
Good Luck!
Posted: 9:44 am on July 8th
Schatzi writes: Response to Gingercat and anyone else with tomato blight problems. Here in Western Washington we had severe late blight problems for several years, seemingly out of the blue. Then it seemed to disappear. As a master gardener, I can track these problems by the number of questions we get from gardeners. It was so bad for several years that I started growing my tomatoes in a small greenhouse. Anything you can do to keep the leaves dry helps, but sometimes even heavy humidity can aid in infection. Early blight is not as severe a problem. Late blight is what caused the potato famine in Ireland in the nineteenth century. Fungicides have not been proven to help much, but may be worth a try. Other than that, pray for hot dry weather!
Posted: 11:02 am on April 28th
dmc58 writes: I'm having the same problems with my tomatoes too. I live in Daytona Beach and was wondering if not having any bees to polinate my vegs is part of the problem. All of my squashes, cukes or any vine that I plant, I maybe get 1 piece of fruit and then the vines don't produce any more- its very frustrating when you put all that work into planting vegs and not to have them produce fruit. I use my own composite, water and feed them, but have hard time growing anything. Any help would be appreciated.
Posted: 12:12 pm on August 26th
gingercat writes: I moved into my home in 2002, since the first summer of my veggie garden, I've had a huge tomato leaf blight problem. Every year I've tried numerous things, so I wouldn't have to deal with blight the folowing year. Nothing helps.
I was wondering if I should start treating them with an organic fungucide as soon as I plant them in the ground this year and continue to spray them every 14 day through out the growing season.
If anyone has any advise I would really appreciate it. I rotate, I plant them far enough away, I only water in the morning and I keep all my tomatoes caged and staked and I still deal with extreme blight every season. I hits mid season.
Thanks
Posted: 6:11 pm on April 24th
HaveGreenThumb writes: Just want to mention the importance of calcium to tomato health. It is very important to help prevent blossom end rot and cracking on the crown. Also helps prevent other diseases by building strong cell walls.

Dolomitic lime can help and there are natural products that deliver calcium to the plant by foliar spraying.
Posted: 10:46 am on April 24th
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