Physon 20

[Chubidubi]

I bought some Physon 20 today and was wondering how to use it for preventive measure. I read all the instructions but rather have the info come from real users.
All my 'chids grow outside 24/7.
Do you use it monthly or weekly? How much do you use? What exactly do you use it for?
Thank you for your help

[Sandy4453]

Wanda, it's good for preventing or keeping at bay, fungal issues. You can use it to spray the plants (1/4 tsp. per gallon), especially in the hotter months and also, to keep the area you're growing in, clean. (During the hot, summer months though, I'm always using a store bought, systemic, fungicide. Physan alone, isn't strong enough to combat all the fungal issues in the humid months.) I have my orchids on metal shelving units that I spray, as well. Whenever you pot or re-pot a plant, it's good to use. I always bathe the plants roots in it for about 1/2 hr. before potting. I also use it to spray the bark once in a while and in summer, about once a month, I put it in the water for all the plants.

[BikerDoc5968]

Wanda, I use a similar...well the same product called RD-20. It is exactly the same as Physan 20. I use it about once a month on plants, benches, floors and any other space in the GH. It gets rid of the algae that grows on the windows in the GH. I use it when I transplant stuff and soak for about 5 min per the lable. The product literature calls for route maintainance at 2 teasp/gal and for transplanting at 1Tbsp/gal. I even spry the flowers so they don't turn all blotchy brown. Since I began using RD-20 I have less problems with crown rot on the phals....the leaves look clean and shiny and no mineral spots and it leaves the GH with a clean fresh fragrance when I don't have flower power.

[Chubidubi]

Thanks Sandy and Doc. You've been a great help.

[D&S Mabel]

Sandy - which systemic do you use? I find that Physan works well except in the July - September high humidity and rainfall months in central Florida too.

Thank!

[Ross]

My systemic of choice is Thiomyl. It's a wettable powder and has a long life once diluted. A long shelf life as well, in powder form. It's my chemical of choice for rots but not fungus or molds. Those require the proper treatment. Physan is great for algae (it actually will do a number on Java moss as well so be careful on orchidarium mounts) as well as common molds. Typically, in the "sterilizing dilution" rate of 1 tblsp per gallon, it will rid regular white mold growing on inanimate surfaces like pots, potting medium, soil, etc. For plants like orchids, you'd want to cut back to 2 tsp (as per the label). I find even this dilution pretty effective for molds. For advanced molds on soils, medium, etc. you'd want to dust with Captan.

[D&S Mabel]

I have Thiomyl but it was not effective against the last outbreak of black rot I experienced. I probably waited too long to start using it as I was getting the first signs of problems when I sprayed. Next year I need to start spraying in advance. That said, maybe someone can answer a couple questions for me?

How long does it take for a systemic to become effective? For example, if I want the extra protection starting on a certain date, would/should I start the application a couple weeks before? More? Less?

If it's effects last a month, how soon before the end of that month should I apply the product again to keep up the protection?

[Ross]

Firstly, (this is general, not specific to your question.) Systemics require active roots to be absorbed. Leaves of most plants (and especially orchids) are poor at absorbing systemic chemicals. You need viable roots. Now, with that behind us we need to get those roots viable. This means that if you have rotten medium or rotted roots, you need to correct that situation first. That is the most difficult. You may find yourself trimming rotted roots, trimming rot of all sorts. Then if there are no (or few) "viable" roots, then you may need to do the famous "sphag and bag" technique, where one places the affected orchid in a plastic bag with a damp bunch of sphagnum or paper towel in a plastic baggie.

[Sandy4453]

Originally Posted by D&S Mabel

Sandy - which systemic do you use? I find that Physan works well except in the July - September high humidity and rainfall months in central Florida too.

His D&S. Organocide (a little pricey but, great) and this past summer I was using Schultz products, both the fungicides and pesticides and was pleasantly surprised. Also use Bayer 3 in 1. All of these are systemic and would recommend.

[Sandy4453]

Originally Posted by D&S Mabel

How long does it take for a systemic to become effective? For example, if I want the extra protection starting on a certain date, would/should I start the application a couple weeks before? More? Less?

If it's effects last a month, how soon before the end of that month should I apply the product again to keep up the protection?

As I understand it, D&S, firstly, in order for it to be thoroughly effective, 3 applications need to be made within a 10 day period and it becomes effective, immediately. Regular maintainence is something that I begin with the summer solstice (or a little sooner). The effects are supposed to last a month but I am habitually on top of this during the warmer months, spraying twice a month.