Corn Gluten Meal for weed control
You can prevent weeds with Corn Gluten Meal. You can find Corn Gluten Meal in health food stores. Use Corn gluten meal in the spring and water it down. This will also keep away seed growth so you will need to choose whether you want to grow the lawn with new growth or prevent weeds.
Compost and Clover
Layer a small amount of compost on your lawn and re-seed with a grass / clover mixture. Water this daily and keep foot traffic away until well rooted.
Clover is a great addition to any lawn. A green lawn requires nitrogen and clover provides this. It also help keep in the moisture so your lawn does not dry out so quickly.
Cut your grass less often
As weather gets warmer always remember to keep the grass longer. This will help the lawn from losing nitrogen and also helps your lawn from drying out.
Listen to your weeds
Weeds are messengers sent by Mother Nature to teach us about the soil. We can kill the messenger but it doesn't change the message. The weeds will always grow back unless we change the soil conditions. Here are a couple of examples:
If you have excess plantain, you almost certainly have heavily compacted clay soil.
If you have excess dandelions, your soil probably needs more calcium and less magnesium.
Aerate your lawn
To achieve healthy plants the natural way, without synthetic chemical fertilizers and pesticides, you need to have healthy, living soil. The organisms in the soil need to drink, breathe, eat, digest and excrete their food and, to do so efficiently, must have plenty of air pockets in the soil. By aerating your lawn you'll leave behind holes through which air, water and fertilizer can enter. The surface of your lawn may look more like Swiss cheese for a few days, but the long-term benefits can be great.
Source: diycraftsandgarden.com