Lawn Weed & Feed vs Feed Only

Another for the lawn experts.

In previous years I've used a combined lawn weed and feed / moss killer NPK 14 0 5.

This year Ive gone down the feed and separate weed killer (Depitox). The feed was 11 5 5 and I managed to apply it just before the recent down pours.

Previously the grass has greened up almost instantly but this year, although it is slightly greener, it isn't as green as with the combined.

Is the combined weed and feed formulated to give the feel good factor of lush green grass or is the addition of moss killer also greening up the lawn ?

Is the NPK balance making the difference ? Should I use a different balance ?

Has last summers brown grass meant that this years lawn is not as strong ?

Or maybe I've been sold some placebo lawn feed

I remember getting instant green grass way back when I used sulphate of ammonia and sulphate of iron solution (when you managed to get them to dissolve)

I'm not concerned that the grass hasn't turned insta-green, more curious

Any thoughts welcomed

 

Depitox is a pro chemical and not for domestic use so I will leave any comments on that.

You are better off using a domestic weed and feed that contains iron which if applied correctly and watered in will turn the grass a deeper shade of green.

all I will say is incorrect use of some weedkillers can have a negative effect on grass.

 

Thanks for the feedback. I didn't realise that it wasn't for domestic use. Its been used as directed on the instructions (1 bar, blue disturbance nozzle at the correct dosage) - I respect your decision not to comment.

The reason I moved away from weed and feed was that it wasn't killing all of the weeds in the lawn.

It sounds like its the iron that was turning the grass green previously. I'll apply some with ammonium sulphate (as soon as the rain stops !)

 

Thanks Andrew, no worries. Online sales should now demonstrate its covered under the pesticide act and if purchased over the counter they should ask questions too but its not illegal to sell to the public but the user must be trained.

yes weeds are resilient to some types of weed killers, selective herbicides cater for most but not all and add in some weeds are resilient it can be hard work.
Its all about matching the fertiliser to conditions to get the best from them. Nitrogen does green up the lawn but iron also helps to green up and toughen the turf. Theres no real answer to whats best but if you water the lawn and the lawns in very good condition a lower N is great with a balanced PK if the weather is warm.

 

Lawn condition isn't too bad but with two dogs, it is never going to be pristine.

Pic from my study just now shows that it is still patchy. Some of the dark patches are where the dog has previously peed so I have to live with this.

As soon as we have a dry spell I'll be scarifying. Having builders in for a month in May set me back with lots of jobs in the garden

 

What day did you apply the feed @andrews ?, it usually takes about 7days to start noticing a slight difference. Its not the best the 4-1 fertiliser for weeds, spot treatment with lawnweed killer is my preferred method.

Don't be scarifying now or soon its to late into the season, the lawn won't recover properly in time, might as well wait until September / October . The lawn probably compacted if you've had building work done so aerating will aid with feed / water / air getting into the root system better, I use a fork but my lawn quite small.

 

Lawn was fed last Friday so less than a week ago. It didn't give that instant green that I get with the combined which was not an issue, more curious as to the reason why.

Thanks for the tip on scarifying - I'll leave till Autumn. Building work didn't compact the ground, it was all done on the drive / areas with chippings. The impact was more that I was clearing up after the builders and then a mad rush to get the bedding planted once the scaffolding was down. It shuffled other jobs further out (the good old 'hours in the day' stuff).
The lawn was aerated two years ago. I was hoping that I could delay until next year or until I can find a reasonably priced aerator which don't seem to come up that often (if at all). I'll look into hiring one localy.

 

Granular iron based feeds with iron never work as fast as liquid based iron.
I too would be cautious about scarifying as the weather may turn hot, fine if you water but sometimes it plays to be safe.
The secret to get a good weed kill is to feed the lawn first then a week or two later spray the weeds if the weather is not baking hot. The fertiliser makes the weeds grow which is good for uptake of herbicide.
Results vary depending on weed type and that applies to liquid and granular.
The other way to green up is seaweed extract as it contains natural iron. Some swear by it and I’ve used it with good results but it’s what works best for you that counts.
As I’ve a dog I don’t use herbicides on my grass and and just cut it, no feeds either.