TOMATO NUTRITION FROM GERMINATION TO HARVEST IN HIGH TUNNELS

Terrance T. Nennich Extension ProfessorFruit and Vegetable ProductionUniversity of Minnesota Extension

Tomato Nutrient Problems

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

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.

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

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

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.

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

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

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

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)

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)

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)

High Tunnel Perspective50 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

High Tunnel Perspective100 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.

Soil Nutrient Research 2008Fertilized Plots

Cobra Tomatoes0- 6 inch soil depth in row

N P KBefore Season 263 252 1349

After Harvest 26 235 173

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.

Tomato Flowering

• Important part of tomato plants life

• Analyzes its production capacity

• Analyzes is maturity

• Can reset its biological clock buy pruning

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.

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

Continual TestingEvery 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.

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.

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)

Questions