Hello
A few years ago I spoke with someone at Ecke Ranch and was told that you guys use lime on the floors to control algea growth.
I spoke with a supplier who told me that ag lime will take a long time to work, so I purchased a pelleted lime that is fast acting.
Could I get some insight on how this method works, how often lime is applied, ect? Will it work on weed barrier?

I believe you mean Spreading hydrated lime for algae control.
Hydrated lime is very different than pelletized,Dolomitic, or marking lime. Hydrated lime will control algae growth by quickly raising the pH and sucking up all availible H ions. It has basic properties. Leaving the area in contact extremly alkaline. Pelletized lime will not control algae.

Yes I meant hydrated lime. So spreading the lime on weed barrier will help with algae control? I must say it looks perfectly horrible spread over the greenhouse floors, but if it works, it's OK. Will one application work or should it be spread once a week, a month or how?
The pelletized lime states that it rapidly raises pH levels in soil, but this will not work in the greenhouse?
Thank you very much for your response. I am finding very little info on this subject.

No, pelletized lime will not work. Hydrated lime will control fungus gnats,algae, and small weeds on dirt floors under benches. I apply once or twice a year. spread out at 2-300 lb/acre

Thanks for the info

We have used hydrated lime for years as a method of algae and weed control in the greenhouse. We spread the lime twice a year using approximately 200 lbs. per acre. It is as you said a little unsightly and can make a mess of your shoes but it had done a great job at controlling algae, fungus gnats, and weeds for us for years now.

We create a slurry of the hydrated lime and water (100lbs/ 50gal) to apply on the floors and under the benches about two to three times per year. After you apply leave 3-7 days depending on humidity etc. to dry. If allowed to dry, it creates a barrier that is very effective for algae and weed control. Water has a hard time penetrating the barrier, so make sure you have good drainage. The other thing to watchout for is if you have galvanized heat pipes. The Lime will speed up corrosion. We like to paint the pipes to limit the exposure to lime, fertilizer and other sprays. You might want to mix in some Copper Sulfate (3-5 lbs/50gal) in order to get some longer lasting algae control.