If fertilizer is supposed to help a lawn grow faster and fuller, can I use starter fertilizer on new sod?
Yes, you can and you should use starter fertilizer when you lay down new sod. You should use a starter fertilizer with a higher phosphorous and potassium ratio than what you typically would use for a lawn. Starter fertilizer should be applied to the soil, not directly on top of the newly laid sod.
The Right Fertilizer
It all starts with the right fertilizer. Fertilizer is rated using three numbers.
These numbers are the NPK analysis, which reflect the ratio of nitrogen, phosphorus, and potassium in the fertilizer:
- Nitrogen helps promote growth and green up your lawn.
- Phosphorus is what helps the roots grow and develop.
- Potassium helps make your lawn more resilient to withstand diseases, and tolerate hot and cold temperatures.
You’ll want starter fertilizer to put on your new sod.
Different brands of fertilizer will have a different NPK ratio, but you’re going to be looking for something around 6-20-20.
More About The Ratio
You may have noticed that there was little nitrogen, but lots of phosphorous and potassium. There’s a reason for that!
Most of the roots from the sod were cut when harvested.
So, once you lay the sod on your lawn, you want the roots of the sod to grow well to the dirt, and phosphorous will help with that.
Without a good root system to establish your sod, it will die, and you will either have to start over, or patch specific spots.
A starter fertilizer also has high potassium levels to help the new sod cope with moving, the added application, and getting set up to the new dirt.
Nitrogen will not make a huge difference initially.
Your sod is already alive and green and too much nitrogen at first would put your lawn’s energy into growing the grass blades rather than roots.
This is why there is limited nitrogen and not too much.
Prior to adding your fertilizer or sod, and if possible you should have your soil test done.
This will check the levels of nitrogen, phosphorous, and potassium:
- If you have high nitrogen in your soil, you won’t want to buy any fertilizer with nitrogen.
- If you have high phosphorous and low potassium, you may want to consider a fertilizer high in potassium greater than phosphorous to get the ratio established.
Fertilizing and Watering Schedule for New Sod
Your new sod is going to be very, very vulnerable, your fertilizing and watering schedule need to be given special consideration.
We put together a program for you.
Day 1
Before applying your sod, your lawn will need to be in the right state:
- You should have put the fertilizer into the ground and given the lawn a good drink.
- You will want to water that water penetrates your soil up to 4” below the surface. If you tilled in your fertilizer, this will not be hard to do.
- Once you applied your sod, you should use a roller to apply some compression, removing as much space between the roots and the soil for the roots to find that fertilizer and water.
- You will wrap day 1 with a light watering to replenish any water you lost throughout the day.
Day 2-9
From here (day 2) to day 5, you’re going to want to water your sod twice each day; once in the morning, and once in the late afternoon.
You should try to avoid walking on the grass during this time.
If you are using a good sprinkler you will have a good chance of watering your entire lawn without stepping on the sod.
You want to check the edges and seams of the sod for any areas that are drying out.
If an area looks like it may be drying out, a hand water will get that area a good soaking.
If you are calling for rain, you probably will not need to water your sod!
You will want to gauge how much rain you are calling for, as a quick shower will not be enough water for your sod for a day!
Days 10–12
During these days you can begin watering only once a day, instead of twice.
On day 10, you’ll still want to leave one corner of the sod, and check for any root growth.
If you see any small white roots extending beyond the thatch of the sod you have done a great job!
Days 13–15
By day 13-15 you should be able to see enough root growth that there is some resistance when you try to pull the piece of sod from the soil.
If you’re at this stage, it is officially time to mow for the first time!
You will want to mow grass with the highest setting so that you only take off the very tips of the grass. At this stage, you can also slow down watering to once every other day!
Days 16–20
During days 16-20, if you see enough root growth and your sod is looking green, you can apply fertilizer again.
Follow the fertilizer instructions and spread the fertilizer evenly.
Now is also the time to start decreasing the frequency of watering to once every week.
Final Thoughts
I highly recommend using a starter fertilizer for your new sod.
This will give the grass and the root system a much better chance of survive after being installed, and a good investment into your lawn.
If you follow the guidelines to apply the fertilizer to the soil, not directly on top of the sod, give your lawn tons of water, you’ll have your new sod looking like lush lawn in no time!