Use of the seed rate formula below in conjunction with a target established plant population (see table below) allows greater control over the final number of plants established per square metre. Use of the formula also factors in variations in Thousand Grain Weight (TGW) as well as germination and establishment. All these factors vary greatly and make a significant difference to the final seed rate. Over-thick crops may lodge, give lower test weights and have higher disease pressure; thin crops will not have maximum yield potential and are not as competitive with weeds.





The table below provides an estimate of the expected plant establishment percentage for different drilling dates of cereals which should be included in the above calculation to determine seed rate. It's important to note that this is only rough guide that is used by the industry. 


Month Plant Establishment%
April Early  95
Late 90
May Early 90
Late 85
June  Late 80
Early 75
July Early 70
Late 70
 August Early 80
Late 85
Setpember Early 90
Late 90



The table below provides the recommended established plant numbers for different drilling dates of wheat. Please note the important comment below the table relating to when you may need to vary the target plant number. The table also gives some example seed rates at TGWs of 45, 50 and 55, assuming in all cases a germination of 95% and an establishment of 90%.

Drilling Month  Target Plant Population (plants/M2) TGW (g) Seed rate in kg/ha
45 50 55
April  100-125 53-66 59-73 64-80
May 125-175 66-92 73-102 80-113
June 175-200 92-105 102-117 113-129
July  200 105 117 129
August 200-250 105-132 117-146 129-161
Setember 250-300 132-158 146-175 161-193

*Manawatu winter wheat growers - use 20 plants/m2 less than the lowest figure above for April, May and June. 



Due to the Excellent tillering capacity of EMPERO and RISTRETTO, seed rates need to be reduced as per the table below.

Drilling Date Target Plant Population
1-15 April  100-120
16-30 April  120-140
1-15 May  150
16-31 May 150
1-30 June 150-200



AMILO tillers extremely well from an autumn sowing but will inherently produce fewer tiller from a winter drilling. 

Drilling Date  Target Plant Population (plants/m2)
April - 15 May 125
16-31 May  150
1 June to 15 July 150-200



Drilling Month  Target Plant Population (plants/m2)
Early - Mid April 150
Mid April & May 175 - 200
June 200 - 225
Early spring 225 - 250
Late spring 250 - 300