Why have parts of my lawn turned yellow after re-sowing earlier in the year? 

• There could be several reasons for your lawn yellowing, it will be a process of elimination.
• Does the lawn need fertilising? This is best done in spring or autumn, to rejuvenate the lawn apply Tui LawnForce New Lawns to stimulate root growth and then 12 weeks later Tui LawnForce All Purpose fertiliser. This can be done in spring or in autumn.
• Poor drainage can cause yellowing, this is often caused by heavy clay soil or not enough topsoil on top of a clay base, this is quite common in new subdivisions.
• Add organic matter to the soil by applying a fine layer of Tui Lawn Preparation mix over the area. Organic matter will help improve soil structure as well as improving water retention in summer and make fertiliser applications more effective.
• If drainage is poor, the soil can be aerated with spikes tied on to shoes, these can be purchased from garden centres or hardware stores, it opens up the soil structure. Place Lawn Preparation mix over the area to fill the holes.
• Another reason for lawns to yellow is grass grub, if the grass is yellowing and there is dead grass on the soil surface, as well as birds like starlings feeding on the lawn, then it is possible you have grass grub. To find out if you do have grass grub, dig down to a spade depth and turn the soil over, you should see grass grub if it is present. If you suspect grass grub talk to your local garden centre of hardware store for a suitable control.
• It may be seasonal, caused by a cold snap, a sudden drop in temperature, heavy rainfall, or frost can cause lawns to yellow.