Growing taties in tyres

[Nicos]

Not rival...just complimentary!!!

[Berr]

Had a hurried conversation with Alan Romans (Name-drop smiley) on this subject recently. I think he said that the tubers are formed on what is, effectively, stem tissue. His concern- with maincrop cv.s particularly, I think-
is with the pressure of the earthing-up soil on the developing tubers below. Not sure I understand, but it makes me think that a soilless compost might be desirable, and maybe container growing should be confined to quick-maturing earlies. Certainly can't argue with Jerry's results. Has anybody had good results with maincrop cv.s?

[Jaxom]

His concern- with maincrop cv.s particularly, I think-
is with the pressure of the earthing-up soil on the developing tubers below. Not sure I understand, but it makes me think that a soilless compost might be desirable, and maybe container growing should be confined to quick-maturing earlies.

Would cutting the compost 50/50 with perlite or vermiculite help? I will be planting potatoes for the first time this year in tubs so would be interested in what others have to say?
Jax

[Berr]

Jax,
I think that would be worth experimenting with. Might have implications for feeding regime, presumably...?

[andrewo]

I always plant in large bins of compost and put in plenty of chicken manure or other manure each year. The problem with putting perlite in that it may raise the temperature of the soil and cause it to be really free draining, also because it is a light material and artificial, I'd be worried that it could be easily swallowed by the potato growth.

[sandersj89]

Andrewo

Perlite is in fact a natural material, it is a mineral, which when expanded by a heating process to form light granules.

It is pretty much inert I believe so there is no problem using it for food production. It wont be asbsorbed by the plant.

The reason to use perlite is for aeration and drainage so adding it to a large tub will reduce compaction but will also reduce the nutrient cocentration some what.

Not sure why it would raise the temperature too much though, what is your thinking there?

Perlite is also often used as a growing medium in hydroponics so in theory if you can get the water and feeding correct you could grow spuds in nothing but perlite, not something I would try at home though!

Jerry

[nick the grief]

Because It's pourus, it will hold onto water & nutrients if you liquid feed So I thing this would be OK.

Perlite is inert but I think Vermiculite will eventually break down & affect the PH, but I can't remember which way - I think it makes it more Alkaline, memories not what it was

[andrewo]

I was told once on an allotment that perlite can be used for drainage and for covering new seeds because it can raise the temperature of the soil because it heats up alot faster than soil. Maybe I'm wrong but thought you should know.

Thanks for letting me know it's a mineral.

[Nicos]

I have never used either of these products and would like to know a little more about them. I recall from geology lessons that they are natural and I recall seeing my poor father struggling with all the floaty bits sticking to everything in the greenhouse and was put off using them.I've seen them used on the tv, but can anyone fill me in with more details please? I usually chuck old potting compost onto the flower bed and don't fancy a speckled border!

[sandersj89]

I use perlite and add it to home made compost to use in the greenhouse for sowing. It increases the air in the soil and aids root development. Spent compost is added to the compost heap and I don't really notice on the beds a year later as it gets a covering of dirt.

Vermiculite I find invaluable at this time of year. Again it is an inert mineral being heat treated mica. You can get different grades from fine to quite chunky. I use the finer grades to cover seed rather than compost. I find that dmaing off problems are non existant and by looking at the colour of the vermiculite it is very easy to see what needs watering.

Again the spend compost is added to a compost bin and then used on the garden and you dont really see it in the ground.

On the point of perlite raising the temp of the soil surface, I cant see how it would. Being white it will reflect light from the surface so should have the opposite effect and being inert there are no chemical activities internally that will generate heat. I have also never used it to cover seed, just to increase air/drainage at the roots.

HTH

Jerry

[sandersj89]

Because It's pourus, it will hold onto water & nutrients if you liquid feed So I thing this would be OK.

Perlite is inert but I think Vermiculite will eventually break down & affect the PH, but I can't remember which way - I think it makes it more Alkaline, memories not what it was

It used to be said that vermiculite was a pH neutral substance but not the pH of the material ranges from 6 to about 9.5 I beleive. The variation is due to different sources of the material, mainly the far east and africa these days, the way it is processed and the level of carbonates in the material and finally the water content.

In the small quantaties I use it I dont thinks it's effect would be noticed.......

Jerry

[Nicos]

Can they be reused or is it difficult to seperate from the rest of the compost?
From a quick scan on google, it looks like perlite is pH neutral and vermiculite is neutral to alkaline as you say!(maybe this is what I need on my acidic peat soil!!!)

[sandersj89]

I dont think you could re use as the grains are pretty small and you could not sieve it out easily.

It is faily cheap though if you bay the larger bags that will last for a year or 2.

HTH

Jerry

[Nicos]

Thanks Jerry!