Maintaining productivity of tomatoes in high tunnels

Tomato    None Given

I grow tomatoes organically in high tunnels. The tomatoes are grown in the ground, irrigated using drip, trellised on a string and with the exception of the cherries, fully suckered.

The plants do great through mid-August, but start to run out of gas and productivity falls significantly in September. I am looking for options to ensure better soil fertility so that the plants can maintain high production through September.

My soil is a sandy loam, I fertilize with Kreher's 5-4-3 (a poultry compost product), and amend with an approved compost and peat before transplanting, but haven't done supplemental feeding during the season. This season, I am considering adding some feathermeal when prepping the house to get some additional delayed N into the ground.

Any suggestions for improving fertility to keep the plants at high production through September?

I'll expand a little upon what I am doing with the high tunnel tomatoes. I'm in Central NY, Zone 5 andI grow tomatoes for several CSAs, my farmstand, and a farmers market. They are grown in a 30X96 high tunnel. I usually grow 6-12 varieties in the tunnel. Varieties I grow include: JetStar, Black Prince, Arkansas Traveler, Big Beef, Black Cherry, Rave, Amish Paste, Dafel, Estiva, Sungold, Suncherry, Yellow Pear, San Marzano, and a few others. The tomatoes are planted in two row beds with 16" between the plants and 16" between the rows in each bed and ~42" between beds. The plants are mulched with straw, a drip line is run for each row of plants and during the warm weather months irrigated 2X a week. A DIG controller runs the drip irrigation.

I rotate the planting between 3 high tunnels. Tomatoes are grown in a tunnel for two years before moving to another tunnel. In the off years, cucumbers and cantaloupe, eggplant and peppers and salad greens are grown in the tunnels.

I have considered fertigation with Neptune's Harvest or equvalent, but haven't pursued it because of concerns with plugging. I fertigated for one season with Worm-Ade, http://www.organicsoilamendment.com/P... ,using a Chemilizer and injecting into the drip lines at a 1:100 ratio, but didn't see any significant change in plant performance. But this may be due to starting too late in the season.

If anyone has experience growing high tunnel tomatoes in a certified organic environment and has cracked the code to extended season productiivity, I'd really like to know what has worked for you.

Posted by: Andy Fellenz (4 points) Andy Fellenz
Posted: April 20, 2013


We have been growing high tunnel tomatoes in zone 6 for several years now. We anticipate our high tunnel tomatoes are going to be our early tomatoes for market as they tend to peter out by mid August. We plant ours out at the end of April and when they go out into the high tunnel they are gallon size. We do around 100 pleats that's just enough to tie us over in our early markets till the 2000 plants of field tomatoes come in. Have you considered staggering your planting, don't plant all of one variety at one time - plant a bit then wait two to three weeks before planting the rest. This may narrow down the problem to decide if it was temperature or if the plants have achieved their life cycle and have begun to wind down production because they are dying. I have always believed that it was more the completing of the life cycle than temperature but I have no solid evidence to back this up. I do know a grower that waits till mid June and plants his tomatoes in the high tunnel and then he has late tomatoes into end of October. A soil test is a good idea before you start amending the soil. We are not organic but in no means conventional farmers either but I have always felt that a lot of farmers are missing the boat on fertigation either not doing it enough or using a fertilizer that is not high enough of a nutrient ratio for what they need. We fertigate at least once a week, on all our crops in addition to early spring lime, compost and fertilizer spreading.

Posted by: Sara Blersch (8 points) Sara Blersch
Posted: April 27, 2013

We grow 'Trust' tomato plants on strings in our greenhouse. I have found that they stop producing well in August due to the high temperatures in the greenhouse. Even with the doors open, sides up, and vent fan running, It is difficult to keep the temps from soaring. Perhaps this may be the problem instead of fertility.

Posted by: Brick House Acres (9 points) Brick House Acres
Posted: April 21, 2013

You might want to test the plants and soil across the season. About 40-50% of the total required nitrogen can be applied before the season and the rest added through your drip system according to this excellent MUS document on high tunnels (page 8: http://extension.missouri.edu/explore...)

The testing (which they describe is) is taking 5th or 6th limb from top of 12 plants/ house, drying that and sending to a diagnostic lab.

You might also consider whether you are getting pathogen build up in the soil? This can happen if the tunnels are not moved around

"Moveable high tunnels can be relocated to a new site each season to facilitate crop rotation and to avoid
nutrient depletion of the soil. Rotating moveable high tunnels to different locations also helps to
prevent the buildup of soil-borne diseases and/or fertilizer salts. Often tunnels that remain in the same
location, producing the same crop for a number of years, will have high levels of soil pathogens, leading
to progressively high disease loads and crop losses. Fertilizer salt build-up can also be avoided when the
tunnel is moveable. If the tunnel is not moved, it is important to remove the plastic every 3rd or 4th year to
allow salts to leach from the soil." http://www.uky.edu/Ag/NewCrops/intros...

Here is a really nice study showed how fertilizers and temperature (and pests like whitefly) all integrated to affect yield; as well as examining this for different varieties. http://www.extension.umn.edu/distribu...

Of course, not all of that may be approved for organic and the fertilizers you use may not be good for a drip since they may clog it up. But the idea of testing does seem a good one to me. Good luck

Posted by: David Hughes (52 points) David Hughes
Posted: April 21, 2013

If the tomatoes quit growing then answer is fertilizer, if the answer is quit blooming, then I have had the same issue and found when the weather is very warm bees do not like to go into a hoop house. I have but flowers near the doors and inside to draw bees in, but found bumble bees are my best polinators. Our small fruit extension agent, recommends 200lbs/acre of actual N for tomatoes, and more to extend the season. I know you are organic, but the plant still needs fertilizer. Do you use any calcium.

Posted by: David Lawson (5 points) David Lawson
Posted: April 27, 2013

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