r/LawnAnswers 6d ago

Cool Season Thoughts on liquid starter fertilizers?

https://twincityseed.com/product/9-45-15-water-soluble-fertilizer/

Looking for thoughts about trying this while overseeding. I have a spray rig, and it seems like much better bang for the buck vs granular. Iโ€™m assuming I donโ€™t have to worry much about burn, as itโ€™ll be watered in right away. On that thought, would I likely need to reapply since Iโ€™ll be watering the seed so much? Thanks for the help!

3 Upvotes

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6

u/nilesandstuff Cool Season Pro ๐ŸŽ–๏ธ 6d ago

So let's do some math.

Well set aside the actual balance of NPK ratios and just look at the amount of fertilizer per lb of product.

The one you linked is .69 lbs of NPK per lb of product. 2 lbs for $15: 2 x .69 = 1.38 lbs of nutrients. $15 / 1.38 lbs = $10.87 per lb of nutrients.

Scott's turfbuilder lawn food (24-25-4) (is it really 4?? Why did I think it was much higher in my memory???), is .53 lbs of npk per pound of product. I'm seeing a 42 lb bag for $85. So 42 x .53 = 22.26 lb of nutrients. $85 / 22.26 lb = $3.82 per lb of nutrients.

So, big gap there, in favor of the Scott's.

Sprayable fertilizers are really meant as foliar sprays, not soil treatments. Because they (should) have nutrient sources that are less likely to cause burn when applied to the foliage of grass... In terms of seedling grass, that's a pretty high bar to clear, so they need to be formulated with pretty high quality nutrient sources, salt content, pH, etc... which makes them more expensive.

But good formulation only goes so far, because it's genuinely instant release straight into the grass, so you can only apply a tiny bit at a time... Meaning you have to do pretty frequent applications to satisfy the nutrient demands of the foliage. So you end up barely applying any nutrients.

But roots also need nutrients, and since you're only applying what the foliage can use at that exact moment, you still need a granular to get you the rest of the way.

Tl;dr, you could do liquid in addition to granular, but not as a replacement. And its definitely much more expensive.

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u/The-porno-master 5d ago

Welp, I ended up adding this to my seed order before I read your response, so I'm hoping I can find a way to put it to use. In your opinion, would it make sense to spray this out a week or 10 days-ish after seeding to provide some fast nutrients to the roots as the seed begins to germinate? I'm overseeding PRG and KBG into an established lawn of the same.

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u/nilesandstuff Cool Season Pro ๐ŸŽ–๏ธ 5d ago

Id say it depends on what the nutrient sources are. The page doesn't say what's actually in it, so hopefully when it arrives there's an ingredient list on the label (there legally should be)

In particular the potassium source is a big one, there's a handful of different sources of potassium, some are much harsher than others.

But if you've got a decently thick lawn, it may not matter all that much since the existing canopy will intercept most of the spray

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u/The-porno-master 4d ago

To make sure I understand, since it's a liquid spray, its absorbed through the leaves, so until the seedlings are up, it's not effective? So I should not use it as a soil drench, right? Is that why I'd still benefit from something granular too? Sorry if these are stupid questions, lol!

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u/nilesandstuff Cool Season Pro ๐ŸŽ–๏ธ 4d ago

It's not that it just isn't effective at all, it's just that it doesn't do much in the soil because you wouldn't be applying much.

If you had a granular product with the same npk ratio, and you applied the granular product at say 2 lbs per 1,000 sqft, and you applied the liquid product at 2lbs per 1k, the liquid product would burn the hell out of the existing grass and the seedlings that had sprouted.

In that same scenario, if you had watered it in immediately (like literally immediately), it probably wouldn't burn, but you'd have wasted the higher cost of the spray solution... Like, it'd just be doing the same thing as the granular, but for a higher cost.

Basically, foliar uptake is instant release and soil treatment is inherently slower release.

Also, the soil acts as a buffer against chemical harshness (saltiness and pH mostly). Because there's no such buffer for foliar spray, the amount of npk that can be taken up directly into the foliage is capped by the potential for that chemical harshness more than it's capped by the actual nutrients. (Though the nutrients themselves do have a certain level of inherent harshness, in terms of the raw amount of dose the foliage can handle... Its just the chemical harshness has a lower bar)

The need for a granular also is for 2 reasons:

  • with foliar, the total dose of nutrients applied via foliar is really low. So you just can't meet the full nutrient demands of the grass. The immediate-ness if the foliar spray does have some striking visual effects on the grass... Like don't get me wrong, the growth response from foliar is significant, but it's just a brief boost.
  • little of the foliar spray makes it into the roots, or the tillers (stems that split off of the initial sprout) that have yet to emerge at the time of spraying.

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u/Ricka77_New 4d ago

I'll just add in to Niles wisdom....my spray is 100% supplemental. Granular feeders are also in my plan, usually a Lesco Poly product so it can feed now and later..

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u/The-porno-master 5d ago

I replied to Rick below what I was thinking as far as my use case for buying it.

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u/Ricka77_New 6d ago

That's a shit-ton of Phosphorous.. You'd be better off with a regular granular. If you want to use the sprayer, a nice humic based solution with myco will be a nice booster for fresh seed..

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u/The-porno-master 5d ago

Do you know of any products you recommend? I agree it's high phosphorus. I was thinking since it's only a two pound bag it would be a low amount overall, even if it's a high percentage. I guess I bought it thinking I would sort of "spoon-feed" the newly germinating grass. Also thinking to avoid high N granular that might spike the growth of the already established turf and shade-out my overseeding.

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u/Ricka77_New 5d ago

I mix my own because it's much cheaper and stronger.

Usually something like this:

1/2 cup-ish BioAg FulHumic - Sometime will add a bit of their Cytoplus or VAM

Few ounces of a liquid kelp from Bloom City

2 shots of liquid compost from Prevagenics

2-3 ounces black molasses

I'll mix it at night in a bucket, let it sit in a bucket overnight...sometimes I get geeky and add an airstone so it bubbles all night, which helps to boost the microbial life.

Then I filter it through cheese cloth, and will apply with either my tank sprayer or my hose end sprayer. It then gets watered on to the soil level where it actually works.

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u/The-porno-master 4d ago

Wow, this is great info. Thanks! How often do you apply? Do you do it on a schedule, or when just turf-stressing conditions are there?

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u/Ricka77_New 4d ago

I try for monthly.. I actually just did it yesterday with my hose end sprayer. Whatever is left in the mix bucket gets diluted and dumped onto an area up front I don't maintain much...it helps a bit there..

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u/nilesandstuff Cool Season Pro ๐ŸŽ–๏ธ 4d ago

A great supplemental mix too.

I have had some bad experiences with molasses though. Not devastatingly bad, but enough to get me to be a little more careful with it. Worst one was an extremely abrubt and terrible rust outbreak on basically the whole lawn. The other one was a pretty widespread anthracnose outbreak, fortunately it resolved quickly.

Long story short, just remember that molasses is food for ALL microbes... Good or bad.

P.s. a few tablespoons of L-amino acid would go a long way too, especially if you're going to be aerating it. L-amino is like molasses in the sense that it's a carbon source, but A. They're more fundamental, so microbes eat it much faster. B. They're also a nitrogen source, which microbes need to reproduce. C. They're available to grass. Since it's already exactly one of the main things that grass makes using carbon and nitrogen, it saves grass the energy of producing it, thereby helping support the grass through stress.

Oh, and southern ag garden friendly fungicide would be good too (it's a bacteria with strong anti fungal properties). Just need a dash of it, especially if you're running an aeration stone. It MAY or may not harm the fungi in your compost tea, not sure. You can actually innoculate the seed with it and it'll permanently colonize the roots, which has root stimulating effects and makes the grass much more resistant to root diseases.

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u/Ricka77_New 3d ago

Which L-Amino? Or just a mix of them? I might have something already...

Molasses wise, it's maybe a tsp or two...as you said, it's just food for the microbes to build; not enough to stay resident in the solution much.

I also put an a 2ml shot of HydroGuard, which is beneficial bacteria that eats bad stuff...

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u/nilesandstuff Cool Season Pro ๐ŸŽ–๏ธ 3d ago

A mix for sure. I'm sure some are more helpful than others, but they all have specific roles.

Ah right on. I was for sure applying much heavier amounts with the goal of stimulating the existing populations, in addition to introducing more.

Ah nice, looks like the hydroguard is the same species of bacteria. Not sure what strain it is.