Growing Big Onions from seed

To make this more inclusive, what are other people's thoughts on growing big onions in big pots? I snap up really big and cheap flexi-tubs (even if they're pink ones).

As used here (scroll down a bit) http://keithfoster.wordpress.com/tag/ailsae/

 

Brilliant post Scrungee...as you are aware i'm an onion growing virgin but this gives me hope as i don't have much room....I'm thinking my GH could be a better option because the temperatures up here take an age to get going...some great info there which i'm clocking
Honest opinion required...whats your thoughts on Mammoth Improved seeds

 

I don't do emoticons, but if I did it would be a thumbs down one.

 

Aw why...i thought i was being clever

 

Most serious onion growers use this method, they can "play" about with soil, feed and such like to ascertain what works for them, we humble mortals often haven't the luxury (or space) to warrant using large pots, therefore I'll recommend raised beds. Having said that, if you've got the pots and the space, go for it!

 

Freddy, i've saved enough for a stamp, your seeds are on their way!

 

New Onion bed coming along nicely, a bit more MPC and topsoil to go, then just a rather large layer of well rotted manure...... Game on!

 

Hiya Vince, thanks for that Sorry I didn't reply sooner, been away for a few days

 

Vince, the seed turned up today

I feel I really need to get my PH down a bit, so I'll be dosing with Aluminium Sulphate in the next week or two(when it turns up). I take on board what you said about manure raising the acidity, but I muck probably half of my beds every year, and the PH is still high.

As my beds are 8ftx4ft, I reckon I'll only be able to go for 18 onions (1ft apart)

Cheers...Freddy

 

Freddy, manuring the beds in Autumn and leaving the frosts and winter weather to do their part will actually reduce acidity, I would wait 'til near planting out time before soil testing and taking appropriate action.

 

Hiya Vince.

My thought process is based on what one does if the soil is too acidic. First, Lime in september, then manure in spring

 

If both applied at the same time the Lime would react with the Manure, giving off Ammonia (as a gas) and thus lot of benefit of the Manure would be wasted, hence they are done several months apart.

My feeling is that Aluminium Sulphate may get washed out of the soil, so would be better applied at the same time as the crop, so that its effect is "current".

I'm a bit sceptical that Aluminium Sulphate will lower the pH in a way suitable for the Onions to benefit, but I have no personal experience.

My thinking is that pH of the soil alters the way in which plants can take up nutrients. In the case of quite a lot of acid-lovers it is an inability to take up Iron (and probably other metals), hence things like Murphy's Sequestered Iron and Maxicrop with Iron, and so on. Its the Iron (or Aluminium) that will make Hydrangeas change from Pink to Blue, and my Mother certainly used to apply Sequestered Iron to the Camillas that she, valiantly but mistakenly IMHO!, grew on her clay, alkaline, soil.

But dunno if Aluminium Sulphate will significantly effect the pH of the soil, or just make more Aluminium available to the plants ? And if the later then is that what Onions actually want out of the more-acid soil that they prefer?

We've probably already talked this round in a circle, so apologies if I am repeating something debated earlier, I was just typing-out-loud.

 

Hiya Kristen.

As I understand it, when adding something intended to alter the PH, it takes time to take effect. According to the instructions that come with Lime, it should be applied in/around September. I was assuming the same for the Aluminium Sulphate. As I said before, I only use composted(bagged stuff) manure. It's all so confusing, makes my brain hurt

 

I'm gonna spend a few minutes playing with Google

 

Good man! Btw, my PH tester turned up this week, just need to get some distilled water