This document discusses tomato nutrition from germination to harvest in high tunnels. It begins by defining key terms like soil pH and plant nutrient terminology. It then discusses analyzing irrigation water, the life cycle of tomato plants, and their fertility demands in high tunnels. The document provides estimates of nitrogen, phosphorus, and potassium needs for tomato plants yielding 5, 20, or 40 pounds each. It also discusses considerations for fertilizer placement, tissue testing, and continual nutrient monitoring throughout the growing season.

1. Terrance T. Nennich
Extension Professor
Fruit and Vegetable Production
University of Minnesota Extension
TOMATO NUTRITION FROM
GERMINATION TO HARVEST IN HIGH
TUNNELS

2. Tomato Nutrient Problems

3. Defining Terms
• Soil pH
– pH = potential of hydrogen
– Greatly affects the availability of nutrients
– Relative acidity / alkalinity
– pH of 7 is considered neutral
– Tomatoes grow best at 6.2-6.5
– Logarithmic scale
– Test both soil and irrigation water
• We often add acid(s) to irrigation water

4. Plant Nutrient Terminology
• Sufficiency: Moving target that varies from
carrying a crop to carrying a profitable crop.
Usually expressed as a percentage.
• Deficiency: Not enough nutrient present to
satisfy even the most minimal plant needs.
• Toxicity: Overabundance to the point of
damaging a plant or causing other nutrients to
be out of balance.

5. Analyzing Your Water
• Test water 1st use for:
– pH
– Alkalinity
– N, P & K
– Clogging particulates
– Fe
• Regularly test for pH and Alkalinity
• Well vs. Spring vs. Stream vs. Pond

6. Understanding The Life of a Tomato
Plant
• Planting - Rapid increase in vegetative mass
• 1st flowering
• Development of fruit
• Ripening of fruit
• Continued development of flowers and fruit
(indeterminate plants only***)
• Determinate types 2nd fruiting potential

7. Tomato Fertility Demands in high
Tunnels
• Not hard to get 5-7 pounds per plant
• Usually enough fertility in soil with a little
extra compost
• 20 pounds per plant excellent fertility
• 25- 50 pounds per plant requires extremely
high fertility, supplied at the proper stages of
growth in proper amounts.

8. Putting a High Tunnel In Perspective
• 1 acre = 43560 sq ft.
• A 26 X 96 High Tunnel = 2496 sq/ft
• 26 X 96 High tunnel = .057 acres
• A little over 1/20th of a acre.
• So when a soil tests requires 300 pounds of
Nitrogen for Example
• 300 X .057 = 17 pounds of N applied in the
high tunnel

9. Fertilizer Placement
• It is important to keep the high tunnel fertility
to a high level through out the high tunnel
• But—
• In high tunnels the fertilizer extraction zone is
very narrow as compared to field production
• 12 inches as compared to 36 inches + in the
field

12. Fertilizer Uptake Zone
• Plants will take up fertilizer from this zone 12”
• Fertilizer you apply much be into this zone.
• Any soil testing you do during the season must be
taken from this zone to be accurate.
• Which leaves little room for error

13. Tomato Fertilizer Use 5lb Plant
N P K
Plant Part -------- lb per ton F.W. ------------
Fruit 3.4 0.4 6.0
Vines 2.6 0.4 3.4
Total 6.0 0.8 9.4
Field Production 13.5 ton: ( 5 Lbs Plant)
81 lbs N/A
11 lbs P/A (25.3 lbs P2O5)
127 lbs K/A (152 lbs K2O)

14. Tomato Fertilizer Use 20lb Plant
N P K
Plant Part -------- lb per ton F.W. ------------
Fruit 3.4 0.4 6.0
Vines 2.6 0.4 3.4
Total 6.0 0.8 9.4
A 50 ton yield/A would require: ( 20 Lbs Plant)
300 lbs N/A
40 lbs P/A (92 lbs P2O5)
470 lbs K/A (564 lbs K2O)

15. Tomato Fertilizer Use 40lb Plant
N P K
Plant Part -------- lb per ton F.W. ------------
Fruit 3.4 0.4 6.0
Vines 2.6 0.4 3.4
Total 6.0 0.8 9.4
A 100 ton yield/A would require: ( 40 Lbs Plant)
600 lbs N/A
80 lbs P/A (184 lbs P2O5)
940 lbs K/A (1128 lbs K2O)

16. High Tunnel Perspective
50 T/A or 20# Plant
• 26 X 96 High Tunnel = .057 acres
• 300 N = 17.1 # in high tunnel
• 92 P2O5 = 5.24 # in high tunnel
• 564 K2O = 32.15 # in high tunnel
• This is a combination of soil and added supply
in the root zone

17. High Tunnel Perspective
100 T/A or 40# Plant
• 26 X 96 High Tunnel = .057 acres
• 600 N = 34.2 # in high tunnel
• 184 P2O5 = 10.48 # in high tunnel
• 1128 K2O = 64.29 # in high tunnel
• This is a combination of soil and added supply
needed in the root zone.

18. Soil Nutrient Research 2008
Fertilized Plots
Cobra Tomatoes
0- 6 inch soil depth in row
N P K
Before Season 263 252 1349
After Harvest 26 235 173

19. Considerations
• Some varieties do not have the capability to
make high yields, especially early cultivars
• Heirlooms are often not high yielding a will
self destruct under high fertility management
• Cultivars will very tremendously
• High Productive cultivars will show stress.

20. Tomato Flowering
• Important part of tomato plants life
• Analyzes its production capacity
• Analyzes is maturity
• Can reset its biological clock buy pruning

21. Nutrition at flowering and first small
tomatoes
• Plant tissue analysis
• Soil test in row
• Adjust fertility program
• Bring Ca to 100% sufficiency
• K+ needs to be above 3% by dry matter
• Nutrients: Potassium Nitrate, Calcium
Nitrate, Calcium Chelate, Potassium
Carbonate, & Magnesium Oxide, fish
emulsions , organic fertilizers.

22. Tissue Testing
• Plant tissue analysis at first flower.
• Tissue analysis:
– 10-15 whole leaves
– Collect from average plants
– Collect 4-5th leaf from top
• Most recent mature leaf
– Paper bags only!
– Overnight or pickup

24. Continual Testing
Every Two Weeks
• Monitor N, K+, Ca & Mg levels
• Monitor irrigation water pH weekly
• Weather considerations
– Day length
– Relative sun / cloud cover
– Day / night temperature variations
• Creating high quality fruit requires careful
irrigating.

25. Fertilizer
• Needs to be added at least weekly
• Up to Flowering 1-1-1 ratio
• After flowering 2 -1- 2 ratio
• Possible 1-1-4 after harvest.
• Added fertilizer should have Micro Nutrients.

26. Tools
• pH meter in good order
• pH calibration solutions (fresh)
– pH 4.00 & pH 7.00
• Plant tissue test kits (mail or drop)
• N & K meters (optional)

27. Questions