Can You Spray Sulphur And Fertilizer At The Same Time

June 8, 2011 8:28 PM

Is it okay to mix the sulphur with some VF-11 fertilizer and spray both at the same time? I think I'm seeing some phosphorus deficiency (red segments on the leaves) so want try and address it and also want to keep up my powdery mildew prevention regime.
posted by zeoslap to home & garden (2 answers total)

VF-11 has an ardent fan base, but analyses of it tend to suggest that it's kind of small beer in terms of nutrients.

For phosphorus deficiencies, you want to give the plants a bit of a hit, so I'd be suggesting something stronger like a high phosphorus liquid fertiliser, or even just a balanced but strong liquid feed. I'd also be applying it to the roots, not as a foliar spray, just because you want to wet the leaves as little as possible when you've got powdery mildew.

Couple of general things. If you haven't already, check soil pH to make sure it's not excessive soil acidity locking up your phosphorus. Also, if you're somewhere with cool soil temp.s and you haven't already, mulch. Cold soil reduces the availability of phosphorus.

Finally, if your soil pH test comes back acid, give a bit of thought to how much of your sulphur is washing off each time you apply it. If there's a fair bit hitting the ground, it might actually be the cause of your phosphorus deficiency.
posted by Ahab at 10:27 PM on June 8, 2011

Urgh I picked VF-11 because it looked to have pretty much no Nitrogen and I don't want to spur growth and the other high phosphorus ones all had loads of Nitrogen too. I hadn't realized that it was so weak (I'd read it as 1-8-1)

Also thanks for the pointer on the sulphur itself possibly causing the lack of phosphorus as I wasn't aware that could be a factor.

To the original question though if I'm already spraying sulphur can I add a foliar fertilizer to the mix and spray both together and kill two birds with one stone (and hopefully not my grapes)

Thanks.
posted by zeoslap at 8:08 AM on June 9, 2011