Second question, my Magellan zinnias eventually fell prey to PM (I think). What's the best way to prevent PM?

Until your message, I never heard of 2B Seeds. Their bulk price for Magellan is competitive. However, they don't seem to be listed in the Garden Watchdog, which would worry me a bit, because they must be a very new seed company.

Notice that Harris also has a quantity price for Magellan that is competitive, 250 seeds for $25.95 which works out to about 10.38 cents per seed. Their listed backorder date is today. GeoSeeds lists Magellan at 100 seeds for $9.30, which is also low. Shipping costs actually become a deciding factor.

It has been several years since I grew Magellan, and as I recall I got a package deal from Parks that was not competitive with any of the prices listed here. Parks currently sells a 25-seed packet of Magellan for $4.95, which works out to about 19.8 cents per seed, which is one of the highest prices per seed that I have seen for Magellan.

From your picture, it does appear that your Magellans did fall prey to Powdery Mildew. There is also a hazy area in the upper left quadrant of your picture that arouses my curiosity. From the standpoint of air circulation and sun exposure, your Magellans may not have been in the best situation.

In the Fall, as the days shorten and the night temperatures grow cooler, zinnias find themselves in a situation very different from what they need to thrive, namely lots of sun and warmth. The zinnias are old and failing and at the end of their life cycle, and they have very little resistance to anything. I'm not sure it makes sense to "fight" Powdery Mildew in that situation. The PM may actually be helping the zinnias by causing them to shift their priority from making new foliage and blooms and to spend what they have left on maturing their seeds.

For the distressed zinnias in your picture, I would have pulled all of them out, cleaned out the bed from any remaining dead zinnia material, disposed of it all in the kitchen garbage as if it were biohazard material, and sent it all to the landfill in the trash pickup. Cold loving ornamentals like flowering kale are more appropriate in the Fall.

If you are inclined to fight PM on zinnias in the Fall, I will go into that in another message. There are some effective things that you can do.

ZM

zen's members page provides a direct email.. should you wish to have a one on one conversation ... see!!!.. it even makes me crabby .... but i am now over it ...

anyway... it appears.. that your bed is 1 to 1.5 feet deep.. against a house.. and a sidewalk ... yes???

if so.. let me suggest .. you are the PM problem.. and the source ...

first.. there are too many plants there..

and second.. i suspect.. your watering is the root of the problem ...

thin the heard to increase air circulation.. as zen suggested ... if you dont like that look.. then you have to deal with the PM ...

PM grows at night ... during the hot dank days of summer ... its not a spring thing ...

the biggest cause.. ever.. in my garden.. was me.. coming home and after dinner.. going out and WETTING EVERYTHING DOWN... in late evening ... what a dolt ... who knew.. lol ...

and lo and behold.. the next thing you know.. PM everywhere ...

also.. there is NO CURE ... only prevention ... and that can be as simple as baking soda in water ... unfortunately .. guess what... when it dried.. it leaves a powdery film on the plants.. lol .. so no PM... but the look is there anyway ... lol ..

and yes.. i used to spread chemicals all over my roses.. back in the day ... i dont do roses anymore.. and i dont do chems.. its just not worth it.. especially if its a late season plague ... you really dont worry about your tulips in late summer/early fall.. so why fixate on these???

so thin the heard.. stop wetting foliage [presuming you do] .. ... and you should reduce the problem significantly ...

ken

ZM, I did locate 2B Seeds on the Garden Watchdog link. They're a family operated company in Colorado that was given mostly favorable reviews. Their shipping is free (over $30 orders), which was my deciding factor.

It was indeed late season when my Magellans developed PM, so I guess I shouldn't have been too disappointed..... And yes Ken, spacing was too close, however I use drip fertigation, so watering wasn't an issue.......

Hi Yankee,

I think the 2B Seeds free shipping on orders over $30 excludes bulk seed orders. I see Magellan in their bulk listings, but I do not see Magellan in their retail zinnia listing. You might want to check into that.

An effective strategy for having good looking Fall zinnias is to make a separate Fall garden planting of zinnias sometime in July or possibly even early August. That gives you rather young zinnias for your Fall display, and young zinnias are much more resistant to disease than old senescent zinnias.

"...however I use drip fertigation, so watering wasn't an issue..."

Actually, watering was and is an issue for Powdery Mildew. Ken said "...stop wetting foliage...and you should reduce the problem significantly..." and you countered that your drip system doesn't wet the foliage. You and Ken are in apparent agreement that wetting the zinnia foliage would help cause zinnia Powdery Mildew.

I hope to change both of your minds on that. It is a myth that wet zinnia foliage invites Powdery Mildew. I have some links to articles that would help dispel that myth, but Ken gave a link to a relevant article, so let's refer to his link first. In the Joe Lamp'l article paragraph titled "So Now What?", the first sentence reads "Conditions that favor mildew formation include dry foliage...". Notice that it said dry foliage. Oops for your drip system.

If you think that was a misprint, down in the section titled "Lesser know options include:" it says "Water - Ironically, dry conditions and high humidity are the most favorable conditions for powdery mildew to form. But straight water is its enemy because it washes off the spores before they have time to embed. However, water isn't something that I promote for control because wet foliage is friend to many other plant diseases."

Joe Lamp'l doesn't give water enough credit. Notice that in this article, in the Cultural Practices section, it says that "In fact, water on plant surfaces for extended periods inhibits germination and kills the spores of most powdery mildew fungi." And in this article it says that, "In the case of powdery mildew, you can actually inhibit infection with frequent sprays of water."

I protect my best breeder zinnias with a combination systemic insecticide and systemic fungicide. That stuff costs too much to use on all my zinnias. But, for all of my zinnias, I use frequent foliar feeds, which inhibit PM, and I also occasionally use GreenCure. GreenCure prevents an impressive list of foliage diseases, including PM. But rain, or even heavy dews, wash the GreenCure off, so that you have to spray it fairly frequently for ongoing protection. It is safe and non-toxic.

This last year, as usual, I used overhead watering and repeated foliar feeding on my zinnias without a trace of mildew on a large zinnia garden. Of course, a freakishly early killing frost early in October took about a month off of my growing season, and that month would have been prone to PM. But PM has never been a problem for me, mostly because I am an enthusiastic foliar feeder.

ZM
(not associated with any product or vendor mentioned or linked)

Heh, guess I'll be going back to overhead watering & foliar feeding my zinnias.... It's just soooo contrary to my vegetable gardening irrigation practices!

2B Seeds did drop shipping on 3/100pks of Magellan mix (off their bulk list). I'll take it. Harris was a bit cheaper but you'll pay shipping......

The idea of starting fall zinnias never occurred to me.....

I use chemicals when needed in my vegetable garden & raised beds, even though there's a huge push for organic gardening these days. If GreenCure will help, I might try it.

Maybe a smudge on the lens?

Hi Eahamel,

It could be a smudge on the lens, but when I first saw the picture, the "misty" area made me think of spider mite webbing. This is an enlarged detail from the picture.

The "fog" seems to follow the structure of the foliage somewhat, increasing my suspicion that spider mites could be involved. Spider mites would also explain the prematurely dead foliage. But I cannot deny that it could be a smudge on the lens. I suppose someone could have exhaled cigarette smoke and gotten a similar effect. I guess it remains a mystery.

ZM