corn seedling

Benefits of starter fertilizers

A starter fertilizer application is key to achieving the highest yield possible. It promotes an increase in early season plant growth, increased nutrient availability, and earlier crop maturity.

Applied nutrients are used more efficiently and provide a greater return on investment for your fertilizer dollars.

Finally, starter fertilizers promote good environmental stewardship because it leads to lower overall applications rates that are placed close to the plant and in the soil.

When should starters be used?

  • On rented ground
  • When soil test levels are lower (phosphorus is the exception, response is still seen at higher test levels)
  • When micronutrients are needed as they have low mobility
  • When fertilizer loss potential is high, especially from broadcast surface applications
  • When soil is out of balance due to a high level of one nutrient
  • When planting earlier
  • When forecasted temperatures are cooler after planting

Salt injury

salt injury on corn photo

Salt injury on corn.

Soil moisture can have a considerable impact on in-furrow fertilizer performance. When dry soil conditions are present, the salts draw the water out of the seed/plant and increase salt injury.

Low CEC soils have less reaction between the fertilizer and soil, causing the salt concentration to remain high in the soil solution. Higher OM levels can increase these interactions, allowing for higher application rates of fertilizer without additional salt injury to the crop.

Tips for safe application

  • Do not use urea or UAN as a nitrogen source for in-furrow applications. Urea converts to ammonia, which is very toxic to seedlings.
  • Do not use in dry soil conditions at or just after planting, this increases the risk for salt injury.
  • Limit applications to 5 lbs. per acre of salt.
  • Switch to a fertilizer that has a low salt index, this allows for a higher rate if desired, or the addition of micronutrients to the blend.
  • Be cautious applying in sandy soils (low CEC, low OM).
  • Proper equipment calibration is necessary to ensure that you are applying the correct rate.
  • Add water as a carrier, this reduces the salt concentration and improves flow consistency.

Type of starters: Pop-up vs. 2×2 Band

POP-UP Benefits

  • Lower application rates.
  • Increased uptake of Phosphorus as it is closer to the plant.
  • Increased fertilizer efficiency.
  • Slightly quicker germination.

POP-UP Drawbacks

  • High risk of salt injury to germinating seeds.
  • Little application of N, K, and S.
  • Early side dressing is required to prevent N deficiency.


Pop-up application method. Applied as a liquid, directly on or in close proximity to the seed.

POP-UP application method:

Maximum rate of 6-12 lbs. per acre N+K²O, depending on row width.

2×2 BAND: Benefits

  • Higher rates of total fertilizer.
  • Ability to apply more N, K, and S.
  • Low risk of fertilizer injury to the crop.
  • Use of dry or liquid fertilizer sources.
  • With dry, easier to mix a desired blend.
  • Allows for later side dressing when the crop needs more N.

2×2 BAND: Drawbacks

  • Takes slightly longer for the plant to take up the nutrients as the root system needs to develop more.
  • Challenging logistically when high rates are used; many planter fill ups.


2×2 Band application method. Applied as either a dry or liquid fertilizer, 2″ below and 2″ to the side of the seed.

2X2 BAND: application method:

Maximum rate of 50 lbs. per acre N or 80 lbs. per acre N+K²O.

Sources: http://www.omafra.gov.on.ca ; https://pubs.ext.vt.edu/3002/3002-1438/3002-1438.html ; http://extension.psu.edu/; http://msue.anr.msu.edu/