Pruning Tomatoes

Boca Raton, FL(Zone 10a)

I ran across this on the internet while I was looking for fertilizers. Please comment on the contents


Tomato plants are usually pruned in three ways, lateral shoots, bottom leaves and fruit clusters. I will attempt to explain each of these parts of the plant and the reason for the need to prune.
Whenever possible, it is better to snap the leaves or fruit off, rather than using pruning shears. Pruning shears can smear the juices from one plant into the wound of the next plant and possibly spread diseases. The only pruning job that will require pruning shears is the removal of the fruit cluster after the all the fruit has been harvested. This procedure may require disinfecting the shears occasionally with rubbing alcohol.
The plant has natural breaking points which will allow the plant to heal quicker and not leave any small remaining plant parts that will later die and allow an entry point for fungus. These breaking points are where a leaf attaches to the main stem of the plant. There is also a knuckle, called an abscission layer located behind each fruit on a cluster. Again, this is a natural break point. The lateral shoots do not have a natural breaking point, so it is recommended that these be removed when they are as small as possible.
Tomato plants would like to become a bush. At each leaf, the plant will attempt to produce a lateral shoot, or sucker. If this lateral shoot is allowed to grow, it will become another stem on the plant. When the plants are grown vertically in a greenhouse, usually they are pruned to only one stem - all lateral shoots are removed. The lateral shoots are usually removed when they are 1" - 3" long. Allowing the shoots to get bigger only wastes the energy of the plant and will create a larger wound when the shoot is removed. Maintaining only one stem on each plant allows better management of plant spacing and helps control the amount of light reaching each plant and allows for better ventilation around each plant. It also keeps a better balance with the root system and will usually produce larger fruit than you would get from a plant that is allowed to bush. With better ventilation, controlling insects is also easier.
Pruning of the lower leaves on tomato plants is necessary to provide better ventilation around the base of the plants, which helps to reduce fungus problems. It also allows the grower to see the fruit as they ripen, making them easier to harvest. These older leaves begin to age and are no longer contributing to the photosynthesis of the plant. As the leaves age, they begin to yellow and turn brown. They can actually begin to attract fungus, which can spread to the healthy leaves.
As a tomato plant grows, the plant will usually produce 6 - 10 true leaves before it produces a cluster of flowers. After the first cluster, the plant usually will produce 3 leaves and another cluster of flowers. In a greenhouse, the plant will usually be opening the 7th cluster of flowers before the fruit on the 1st cluster is ready for harvest. At this point, the plant would have a full load of leaves (approximately 18 - 21 leaves) for proper photosynthesis and fruit development. A grower usually attempts to keep this number of leaves on the plant throughout the season. Many growers will harvest fruit from 20 - 30 clusters during a growing season. When pruning bottom leaves, only 2 - 3 leaves should be removed at one time. Removing more leaves may cause excessive moisture loss that can shock the plant. If more leaves need to be removed, it is best to wait 2 or 3 days to allow time for the first wounds to scab over.
Each flower cluster on a plant usually consists of 4 to 8 flowers. A grower usually pollinates these flowers and then examines the small fruits when they are 1/2" - 1" in diameter. Four fruit that appear to be developing #1 quality will be allowed to mature on each cluster. Any extra fruit - or fruit that is misshapen will be removed before the plant wastes energy developing the fruit. A tomato plant is only capable of holding about 28 fruit at any given time. If excess fruit are allowed to set on the early clusters, the plant will abort the fruit from later clusters. This can cause peaks and valleys in production that can cause marketing problems.

Houston, TX(Zone 9a)

Pruning... A perennial tomato topic whose presence indicates that spring must be nearly here!

I have always encountered a problem with the provided instructions in even the most well researched articles about pruning. They invariably start with the suggestion that I "find the main leader". Most of the heirlooms I grow are spoiled children, and do not follow such well-ordained ideas as having an identifiable "main leader".

My Cherokee Purple last year stunted itself by growing a large flower at approximately 1'. It then remembered it was a tomato plant and proceeded to sprout no fewer than TWELVE main leaders, each of which produced a fabulous cluster of fruit.

I understand there are many reasons for pruning. Most of us are limited on space and want to pack more plants into the same space. The other extreme is having nothing but space, but no budget for hundreds of tomato cages. The Florida Weave seems to do best with a modest amount of pruning. And finally there are those who are curious about growing the biggest tomato or other experiments.

My hat is off to all of them. I let my tomato plants do what they will in their 6' cages. Within six weeks of planting, I discover branches reaching not just into adjoining cages but sometimes two cages away.

This message was edited Mar 6, 2008 6:10 PM

Evansville, IN(Zone 6b)

Bob, the article you quote appears to be advice for growing indeterminate tomatoes in the classic cordon style typical of glass house cultivation, outdoor single stake support, and possibly closely planted (18" - 24" spacing) trellis supported. You might also find it helpful for espalier of some fashion up a support system like cattle panels or grapevine type post and wires. Of course, with espalier, you might want to let a few side shoots develop into horizontal laterals along the wires between the posts.

The text you quote isn't helpful in its entirety if you use wire cylinders, Florida weave, or some other more common method of supporting tomato plants in outdoor home or market gardens except the good advice regarding sanitizing pruning tools between plants or preferably hand-snapping/pinching off leaf stems and young lateral shoots rather than using a cutting tool. However, I have injured plants by hand removing foliage at times because I accidentally or carelessly stripped off fibrous tissue down the main stem leaving a raw, open scar.

Personally, I find pruning necessary for the health of the plants (air circulation issues and removal of excessive foliage from rampant plants), but don't do it in my garden quite so radically or so methodically as described in the article you quote. However, a friend of mine who grows in hoop houses, both determinates and indeterminates ... two plants per 5-gallon grow bags filled with coir and fertigated four times per day with 4-18-36 plus calcium ... does extensively prune both his cordon indeterminates as discribed in your article and his Florida weave determinates in a fashion recommended for the cultivars he uses. Yes, some determinates are so rampant that the breeder specifically advises pruning to produce top quality market fruit. And his tomatoes are absolutely beautiful with a high percentage of #1s.


This message was edited Mar 6, 2008 7:26 PM

Pepperell, MA(Zone 6a)

I have some interest in understanding the prunning of T-Plants. We've been having a terrible time with blight and god knows what else the last several years. And it seems reducing the foliage might help. I even went so far as to buy (download) a book advertised on DG called Organic Tomato Magic by Kaeper Postowski. He says a T-plant only needs three (that's 1, 2, 3) leaves per plant. And also claims it increase tomato yields. Any thoughts?

Evansville, IN(Zone 6b)

Leaves are essential for photosynthesis. Photosynthesis produces carbohydrates (sugars) that feed/build the plant and sweeten the fruit. In other words, leaves are the sugar factories and the fruit is the sugar storage room.

The idea of pruning is to balance the foliage with the needs and challenges of the plant. Reducing the foliage to three leaves does not strike a balance.

Example: One reason (not the ONLY reason ... so everyone remain calm when I say this) that short stake, determinate, concentrated set, modern commercial market tomatoes lack flavor is there is not a balance of fruit to foliage. The fruit side of the equation is way too weighty for the foliage side. On the other hand, old fashioned, indeterminate types produce less fruit and much more foliage per total fruit weight AND the fruit production is spanned out over a longer period as it's being serviced by the foliage to fruit ratio. Hence, more sugars per fruit ... more flavor.

So ... do I have any thoughts about that book by Mr. Postowski? YES ... try to sell that book on ebay for as close a price as what you paid for it and find a source of tomato growing technology that provides truth rather than fantasy.

Pepperell, MA(Zone 6a)

Pennyrile - thanks for the info. Did not pay much for the book so it is not a big deal.

Albersbach, Germany

wha, I ordered the book from Mr. Postowski and promptly asked for and received a refund. When asked why by Mr. Postowski I told him growing tomatoes in greenhouses and using cow manure is nothing new to growing tomatoes to increase production and some of the procedures he quoted for removing foliage from tomato plants have been used for years by commercial tomato greenhouse growers here in Europe. To his credit he responded to a similar thread concerning his book at GW with not much success.
Normally I prune leaves at the bottom of the plant for increased air movement and remove some but not all suckers to control the size of the plant. As I grow most of my tomatoes in 5-7 gal containers I feed my plants on a regular basis with organic nutrients and mycorrizae and by regulating the NPK I can control the growth of the plant and fruit somewhat except for the climatic conditions as I do not grow in greenhouses.

Pepperell, MA(Zone 6a)

amiduetch - Thx for the information. I bought his book last november and did not really read it until recently when t-season was approaching. It is obvious now it is more in line with comm. growers. There was recently a show on TV on a grower in Maine that supplies T's throuigh out new england and all the plants looked like Mr. P described.
My goal really was to beat the wilt desease and/or fungal desease I've had the last several years. The garden is in a wet area and is raised 3x4'. Still it holds water and has an underground stream I found last year. No option to move the bed as I have built a 3' wide 4' rock wall around it (the yard slopes down into a wet land) and filled with dirt. a lot of dirt!!
We plant about 50 t-plants so we still get plenty of fruit. Although it is painful to watch them die to decease and it spreads to the eggplant as well. We tried one anti-fungal (dracron??) that seemed to slow it down. We began that late so this year we'll start early and try to trim and create more air circulation.
I'm open to all suggestions!!!!

Evansville, IN(Zone 6b)

I guess I'm gonna have to buy that daggone book, because I cannot imagine ANY tomato plant in full production with only THREE leaves :::gasp:::

In a greenhouse with indeterminates grown cordon style, yes, the growers strip off the lower leaves as the fruit ripens, leaving only the leaves above the lowest unharvested cluster of tomatoes. But even then, and even if the grower is harvesting at the earliest breaker stage, there would still be several smaller fruit and flower clusters above that lowest fruit truss. Therefore, since indeterminates have three or more leaf nodes between flower clusters, plus the emerging meristem, there would be more than three leaves on any continuously producing plant.

With determinates, a grower certainly wouldn't reduce the foliage to three leaves, or 90% of the entire potential crop would be destroyed with the removal of the lateral shoots.

So, this "3-leaf" pruning technique remains a mystery to me. Anyone want to sell their copy of this mysterious book CHEAP?


Albersbach, Germany

wha, Mycorrizae and Actinovate.Run a google and see what you think. Also mulch your plants.

Pepperell, MA(Zone 6a)

amideutch - i check them out.

Cibolo, TX(Zone 8b)

pruning is not an option for me. Jusr let them grow.

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