My war on powdery mildew. With potassium bicarb and sesame oil .

[SmittenGarden]

This is sort of a rolling first week review of my attempt to beat the mildew with sesame oil and potassium bicarbonate. Because before I wasn't able to find any experiences on here with potassium bicarb I though it might be of interest to others.

Ive been waging an unsuccessful war with powdery mildew pretty much since few weeks after i first planted. Being new at growing veggies and gardening its pretty much beaten me.

I had/have three determinate tomato plants in one swc that got hit so and that many of the tomatoes ripen rotten.

I have two zucchini in another container that massive and lovely that were hit first. They got so bad that I'm pretty much expecting them to be goners and bought a new baby zucchini plant that I planted in a gallon container on its own till expecting to have to replace the two big ones. And I have a indeterminate tomato in a swc with a bell pepper and even that tomato (newer than the other three has been hit)

I've tried organocide 3 in 1 but I found that I would spray the plants every day for 3 or 4 days till the mildew had turned brown (I hate using that stuff because its makes me feel yucky from spray back) and then if I left it two or three days the whole zucchini would be riddled again.

Well I wasn't able to go out and spray for a couple of weeks and it gave the mildew an upper hand. My entire zucchini plants were white and fuzzy and we stopped getting flowered and barely any fruit. It was at that point we bought the new zucchini and placed it the other end of our patio. I realized the to,stores were bad too. So my husband helped me prune the tomato plants and the zucchini as best we dared to see if it helped restore at least the odds in our favor. But the next couple of days what we didn't cut because just as riddled.

It was at that point I realized the baby zucchini was covered all the way up its stem on the new flower buds and leaves.

So I tried a 30% milk with water spray. I sprayed the life out of every plant, including baby zucchini...... The next day I went out and saw absolutely no change in the mildew. Only white dried stains on my fruit.
And that's when I began to panic (I've spend a lot of hubby's earning on these fruit and veggies.)

And even though I couldn't find anyone on here who had experience with it I ordered some potassium bicarbonate off of amazon (been looking for it for a while and couldn't find it.)

I found a recipe online for 3 tablespoons of potassium bicarbonate, 3 tablespoons of sesame seed oil and a couple of drops of Castile soap in 1 gallon of water...... So I grabbed a bottle of dynasty from the supermarket and mixed it all up in an old gallon milk container. Shook it up well and sprayed the life out of every one of my fruit and veggie plants last Thursday....(I particularly drenched baby zucchini). I think I used about a half gallon that day. I'm pretty sure I didn't get every speck of mildew on the bigger plants as they were bad and big and I started to cut my hand on the spray bottle.

Next day I cautiously looked at baby zuc

I kid you not there was no white anymore. Just a lot of brown where the white had been. I was gobsmacked. I wish I had taken pictures before and after. Before it was pretty bad and looked like it had had it but now it looked like..... A lot of dead brown and some green but I couldn't find any live mildew anywhere.

I looked at the other plants next...knowing I had missed spots and there were more brown than before and what seemed like less white. But they still had mildew because I missed so much. So I sprayed the other half gallon trying to get as much of what I missed and drenched baby zuc again to be sure. The next day I noted a lot less white fuzz on my plants with a lot more brown.

So I waited to see how long I could go before I needed to spare again.....which was Monday. I saw what I thought were very small white line on the dead edge of baby zuc's leaf. So I mixed up another gallon and had my hubby help me prune some of the dead or really festering bits before I watered and re sprayed another half gallon (which seemed to go further than before.)

It's now Wednesday.....I'm hoping I got so much of the powdery menace on Monday that I can go further than 3 days between sprays. I have to say I was in awe at the change in the mildew after just one spray. It also didn't seem to bother the grasshopper in my big zuc's at all who got drenched twice. (Little git is still out there ) and there's new growth (healthy looking) on my big zucchini. I'm hoping that perhaps they will have new blooms again and fruit. As they seemed to have stopped the other week and I was sure they were goners. It's looking like the mildew has gone down a little on my Tommy's and I am hoping I've saved baby zuc just in time.

I'll post agin the next time I spray. I'm hoping I can at least stretch it out to a weekly preventative spray. As the recipe stated it was for both cure and preventative. I just don't have the time to spray every two days. So fingers crossed this method works

[z_willus_d]

I'm glad you found a recipe for success. I've thought I had P.M., but perhaps I did not. At the time, I tried Green Cure, which is a potassium bicarbonate product. It didn't solve my problems, which are likely systemic coming up from the roots rather than a foliar/fungal-mildew thing like P.M. I'm curious what you used for the potassium bicarbonate? What's dynasty? If you do a search for "GreenCure" or "green cure" here, you'll see some other comments on it. Depending on how many plants you have to treat, it can go from very economical to not so. In my case, I had to use half the jar to spray everything I had at the time top-to-bottom.

Thanks for posting your success and results.
-naysen

[Crandrew]

thanks for sharing. I also life in Socal and am plagued with Powedery Mildew each year. I'll have to remember this for next year. Did i miss it or did you not mention where you procured the Potassium Bicarbonate.

[Rockporter]

Originally Posted by Crandrew

thanks for sharing. I also life in Socal and am plagued with Powedery Mildew each year. I'll have to remember this for next year. Did i miss it or did you not mention where you procured the Potassium Bicarbonate.

I just found this article, check your local hardware and garden centers.
http://www.gardenguides.com/84445-bu...carbonate.html

Thanks OP for posting this great information, I will be trying this next season.

[SmittenGarden]

Sorry guys life took over and little has been unwell. I bought a bag of potassium bicarbonate from amazon. It's used in wine making and says so on the bag but the description on its amazon page was used for gardening too.

The dynasty I was referring to was the sesame seed oil. I just bought plain sesame seed oil for cooking. Not the chilli flavored one.

I have yet to spray again but two days ago I saw it had come back on the big one (zuchinin) so I'm going to spray again. One thing I did note though is a few days after the second spray a lot of the leaves I have sprayed were looking brown and scolded...... I freaked. But I think I may have made the mistake of spraying in the sun....I tend to pop out when ever I have the opportunity to (when my husband or mother in law will watch my daughter for 30 mins and also let me have a shower after, as its icky spraying stuff in the garden.) so it tends to be around any time between 2 and maybe 5 ish pm...I think that's too much sun. I thought I read not to spray water in full sun on leaves because it will burn them and then I go spraying frying oil in so cal in what is still pretty full sun. What a plonker......so tomorrow I will do it after 5 at the very least.

[riceke]

Do you think that there is any difference in using any other type cooking oil other than sesame? Or do you think that there is something in sesame oil that has an advantage? I've always used horticultural summer oil with good success and even canola oil but sesame oil is a bit expensive and just wonder what the difference would be. All oils act the same by smothering insects but on mold or mildew I don't understand its purpose.

[SmittenGarden]

I have no idea....the article I read that gave me the recipe said to use use oil. In their descriptions of oil. Sesame was the only one I could think of as being easy to get. To be truthfully honest my Home Depot and OSH have been very lacking when I wanted to buy certain products. I couldn't even find the bt. So I just resigned to using an oil I could get anywhere. And I was getting shopping at wholefoods that day so.... Sesame it was. There was other oil options I just had never heard of them or didn't know where to buy it.

[SmittenGarden]

http://urbangardenmagazine.com/2009/...n-hydroponics/

This is where I got it (recipe and choive of oil) from if you scroll down to oil sprays it talks about botanical oils rather than distillates and says neem oil, sesame oil etc have fungicidal properties. Little lower down it covers potassium bicarbonate and gives the recipe I used.

[SmittenGarden]

Though the recipe another poster shared earlier used less potassium bicarbonate per gallon than mine.....perhaps I'm using too much? And that's why my leaves looked wilted and sunburned/brown yellow?

[riceke]

SMITTEN: Thanks for the explaination. Supposedly NEEM oil also is used for insects as well as fungi and some diseases. The big box stores carry it...sometimes.

[Wi-sunflower]

Actually you were probably correct with your first guess about spraying with the oil in the sun.

I've used the Horticultural oil in the past and it advises to NOT spray in the sun. Very early in the day or better, late in the day when the sun is dimmish, or cloudy.

Carol

[SmittenGarden]

Originally Posted by Wi-sunflower

Actually you were probably correct with your first guess about spraying with the oil in the sun.

I've used the Horticultural oil in the past and it advises to NOT spray in the sun. Very early in the day or better, late in the day when the sun is dimmish, or cloudy.

Carol

Thanks I thought as much....only problem is being in so cal it's mostly always sunny....and having a toddler I never seem to grab a few minutes spare at the right time. :/ so I've been doing it in full sun I guess.

[Rachel W]

I need to make up one of these recipes today. Can regular baking sofa be used as the sodium bicarbonate?

[JamesL]

Neem and probably other oils are effective for insects. I have had good success with potassium bicarb and molasses in lieu of soap for mildews.
I don't think I would mix the 2 though. Oils can inhibit pollination and pollinators don't particularly like Neem.
I usually only spray Neem on the whole plant early in the season before flowering and use it as more of a spot spray if I see aphids and the like after that.

Sodium bicarb - should have some effect, but it is not known to be nearly as effective as potassium.
Everyone's mileage is always variable, I think it is always worth experimenting to see what works for you.

[SmittenGarden]

Originally Posted by Rachel W

I need to make up one of these recipes today. Can regular baking sofa be used as the sodium bicarbonate?

I asked this once before on here and was steered towards the potassium and it was a natural element plants need and the concern of sodium build up in soill being too much but I have seen sodium bicarb recipes when I was looking online. I just have no knowledge or experience to know this answer.