the neighbor plants one patch of flowers every year.. on his half acre.. he plants one bed 3 by 10 feet of zinnia .. the seed of which he saved from last season ...

and he just takes that plastic grocery bag.. and crushes the heads.. and lets the wind lay the seed down on the soil ... and by august.. it is 3 feet high .. and packed with flowers ..

and he usually invites me over when they are about 2 or 3 inches big.. and i harvest a dozen or so babes ... on a rainy day.. and move them to my garden ..

frankly.. i dont think spacing is all that big a deal.. especially when you have limited space..

come the middle of summer.. you can always take out a plant or two.. to give them more room.. but one thing for sure.. it wont be time.. to sow a few more seeds ...

good for you for thinking about it.. good for you.. to be doing the research on it..

just dont get wound up on it ... they are zinnia .. not some foo foo hard to grow problem plant that needs perfect spacing ... know what i mean??? ...

ken

Not sure what you mean by the "smaller height zinnias" but you might want to give the Profusion or Zahara zinnias a try. I grow the Zahara Zinnias (Z. marylandica) each year and they can be spaced very close without any problems. I usually plant them about 2 feet apart but I'm sure they could be even closer. As with the Profusion zinnias, Zaharas are highly disease resistant and known for their ability to withstand heat, humidity, and drought.

Art

This might help you envision... Somebody's Flickr pic. I don't like the creepy row thing, but you get the idea of their size. If you planted those 3 feet apart, they would be lost in the mulch, like bits of confetti. Probably a little farther apart would be good with your long season though. There will be side-branching, especially when you start deadheading flowers, and if you encourage such from the get-go with your seedlings or babes in flats.

"I would like some advice please on whether the smaller height zinnias can be planted a little closer than that."

Sure, you can and should plant the smaller height zinnias closer. The "spread" of a zinnia is more or less proportional to its height. The seed packets usually have some guidance on how to space them. Remember that the root system is also proportional to the zinnia height, so the compact varieties have shallower roots and can suffer distress from dry weather quicker.

ZM

"...but I wanted to do overhead watering for the new beds. Is that OK?"

Most gardeners and books say not to overhead water your zinnias, saying that it will cause Powdery Mildew. Actually, water application is a preventative for PM, but wet foliage will promote several other zinnia diseases, including Alternaria blight and possibly Southern blight.

But I say, if it is significantly more convenient for you, then overhead water. I do it, as well as foliar feed my zinnias. I protect my highest priority breeder zinnias with a product called Bayer All-In-One Rose & Flower Care. You might already be using it on your roses.

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

and the overhead watering.. wetting of the leaves.. is ONLY a problem.. if you wet the leaves in the evening ...

overhead watering.. or wetting the leaves.. is irrelevant.. if you do it.. with plenty of time for the plants to 'dry' by darkness ...

its a mildew.. it grows in the dark ...

and using baking soda in water.. is a simple PREVENTATIVE ... should you wish to avoid hardcore chems ...

key word.. prevent.. no cure once its there ...

the other thing is air movement ... which becomes problematic in a bed where things are stuffed together ... as compared to your original spacing issue ... gaps between plants.. perfect spacing ... increases/allows air movement ...

all subject to me having no clue how this might all be different in houston .. and its zone ...

ken

I think baking soda and Miracid must do the same thing, change the pH to be inhospitable to fungi on a surface.

I agree with most of what you say, but not everything:

"...and the overhead watering.. wetting of the leaves.. is ONLY a problem.. if you wet the leaves in the evening ..."

Actually, wetting the zinnia leaves in the evening is a good way to prevent Powdery Mildew. The idea that wetting zinnia foliage causes Powdery Mildew is widespread enough to qualify as an urban myth. That myth should be exposed for what it is, a myth. The fact is that water kills zinnia Powdery Mildew spores, and several other species of Powdery Mildew spores as well.

But I am not asking you to take my word for it. Notice that in this reference it says "The general advice to inhibit the spread of fungal diseases is to avoid wetting leaf surfaces. In the case of powdery mildew, you can actually inhibit infection with frequent sprays of water." And, for a second opinion, in this reference it says "In fact, water on plant surfaces for extended periods inhibits germination and kills the spores of most powdery mildew fungi."

There are more effective controls for Powdery Mildew on zinnias than water, but water should be given credit for being part of the solution, and not part of the problem.

ZM

you said: I agree with most of what you say, but not everything

==>> and that is why i like GW.. its more of a conversation .. rather than a lecture ... i picture us sitting on lawnchairs in the garden.. shooting the breeze [reducing PM.. lol] ...

when all of a sudden .... you baffle me with species specific advise about zinnia and plants going into darkness with wet leaves ...

i was speaking in generalities [and that can always be problematic...] ... who knew zinnia were different ... well.. you did.. lol ..

do NOT ever take anything i say about zinnia as anything other than speculation .. i mean really you are the Zen master of zinnia ... BTW.. why not the ZINman??? ... lol

have a great day ...

wait.. but back to lucy .. plant one foot of the bed .. wait two weeks.. plant another foot.. wait two weeks.. etc .. do try serial plantings.. what do you have to lose ... but there will most likely come a time of the season.. when the weather is just not favorable to sowing more plants ... as it just wont be favorable to tiny babes making it thru heat and blistering sun.. short of starting seed in a protected area .. and being moved into the garden ... what do you have to lose??? .. and jam them in there.. you can always 'thin' out a few ... but you cant usually be adding new ones.. late in the season ...

ken

If you deadhead, they will rebloom, and in the spring and summer you can deadhead until about now, then let them dry and collect seeds. (I need to get some seeds from the two plants I've had blooming since late spring)

The profusion zinnias and other small ones can be planted close together. The taller ones can get 3-4' tall and wide and really need some space, though.

Funny thing to watch: if you give a single plant much room, it will develop into a great specimen. I had one Tagetes tenuifoia crowding a young plant of a upright Geranium/ Pelargonium zonale. After a while I shovel pruned the Pelargonium and at the end of the season, the Tagetes tenuifolia had grown into a huge beast.
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If you space them really close those plants react to the competition, the single plant probably stays more narrow and the overall effect is more like a meadow: kind of a dense crowd.

Those Zahara types I would space about 8 inches apart, than you should get a dense cover after a while, but still have enough space so the individual plant develops nicely.

Have fun with your Zinnias, good luck,

bye, Lin