Veg container mix - What's your recipe?

[Valleyman]

After getting my 200L of vermiculite delivered today I had a bit of spare time and made a batch mix of my tomato potting mix ready for the season ahead.

My tomato greenhouse recipe is:
2 scoops of sieved soil
8 scoops of multi-purpose compost
2.5 scoops of vermiculite
20g water retaining crystals
10g epsom salts
A handful of slow release plant food.

And then multiply this up for the quantity required. The Epsom salts are a new addition this year after noticing some magnesium deficiencies in previous years (I will spray more if required later), and the water retaining crystals are being trialed on some plants, but not all.

However, I am always looking for ways to improve. Any ideas? What is your mix?

[Kirk]

Mine is always about the same = compost and manure. All I tend to do is vary (slightly) the proportions. For tomato's I would likely aim at 3:1 (Compost:Manure) and for potato's up to a 1:1 mix. Usually depends on the amount of compost and manure I have around or have bought. Also the veg to be grown.

At the end of growing it then gets deposited on the garden or veg bed.

[Penellype]

Depends a bit on what I am planting. My basic mix is home made compost or last year's tub contents, mixed with a couple of coffee lids of BFB per 1/2 tub trug of compost. This time I'm trying mixing in a dollop of vermiculite for some plantings. If I have it I may add some well rotted horse manure or leaf mould as available. I try to avoid using compost that has grown crop A for crop A again, although this isn't always possible. I'd plant potatoes straight into that. For carrots I make sure that I use the home made compost that has some soil mixed in rather than recycled MPC, and I would tend to sieve it whereas I don't bother for potatoes. For leafy veg like spinach and cabbages I would put a good layer of the mix at the bottom of the pot but the top layer would be fresh MPC so that the young plants got a good start with reasily available nutrients. For tomatoes I buy proprietary tomato compost (usually the large sized tomato grow bags, but I empty the compost into other containers). I don't trust myself to get the feeding right for tomatoes which are particularly fussy. For seeds I always use bought MPC as it is sterilised.

[maverick451]

I got really good results from Mels Mix (square foot gardening)

1/3 vermiculite - large or ex large chunks
1/3 Peat
1/3 compost of different sources

[beeterforit]

The best addition for my toms mix is 15% chopped seaweed the toms love it
If I did not live by the sea I would make an excursion to get some

[TrysHard]

for potting on about (ish)

4 parts MPC
1 part vermiculite or perlite

Old mix goes into raised beds or compost bin.

Seed sowing

Pellets have been good this year and no mess for starting off indoors or 50/50 Sieved MPC and Vermiculite

[More basil]

I would be interested to hear if there's a great difference between using vermiculite and perlite in your 'recipe'?

[Valleyman]

They are both pretty similar:
Perlite- Holds less water, adds more aeration, better draining.
Vermiculite- Holds more water, doesn't aerate as much and can reduce watering needed.

I use perlite for Mediterranean plants to create a "poor soil", or those plants that need to dry out alot between watering, but for crops that require a lot of water like Toms, then Vermiculite is better suited IMO. However, I will be honest.... I have never done a side by side comparison.

[Kristen]

10g epsom salts

The Epsom salts are a new addition this year after noticing some magnesium deficiencies in previous years (I will spray more if required later)

I suppose the Magnesium doesn't leach out? I water my tomatoes with Epsom Salts, prophylactically before they show symptoms, as they form the first fruit. I wonder if including in the potting mix might be "lost" before the time in the growth cycle that it would be first needed?

the water retaining crystals are being trialed on some plants, but not all.

I've gone off them (even for my Tubs of ornamentals, as spent compost from them may well get reused on Veg) as I read something by Linda Chalker-Scott about the chemistry of the breakdown products from the water retaining gel being not well understood and thus the potential for them to be discovered, in years to come, as being hazardous.

[Penellype]

I've gone off them (even for my Tubs of ornamentals, as spent compost from them may well get reused on Veg) as I read something by Linda Chalker-Scott about the chemistry of the breakdown products from the water retaining gel being not well understood and thus the potential for them to be discovered, in years to come, as being hazardous.

Hmm, interesting. I've used the "water slices" in my tubs of ornamentals but not the crystals that you mix with the compost, but I do sometimes wonder if the compost you buy contains some of this stuff, as they tend to say on the bag "holds more water" or something similar.

[Valleyman]

I suppose the Magnesium doesn't leach out? I water my tomatoes with Epsom Salts, prophylactically before they show symptoms, as they form the first fruit. I wonder if including in the potting mix might be "lost" before the time in the growth cycle that it would be first needed?

I suspect it will leach out, but i like to think trace amounts will stick around. Also anything that leaches out should hopefully be recycled to when it's needed, as i don't free drain my toms in the greenhouse. I have them sat in big black trays, and i water from the bottom by filling the trays. Therefore anything that leaches out will stay in the trays and get taken up as and when needed.

I'll probably foliar spray with epsom salts once the plants get established as well, and none of my outdoor toms will be in trays so i suspect leaching of the epsom salts will occur rapidly. But then again outdoor toms will be cast down with blight and rot anyway :-(

I've gone off them (even for my Tubs of ornamentals, as spent compost from them may well get reused on Veg) as I read something by Linda Chalker-Scott about the chemistry of the breakdown products from the water retaining gel being not well understood and thus the potential for them to be discovered, in years to come, as being hazardous.

From what I have read it is all down to the acrylamide formed when they break down, which is a neurotoxin and certain studies on some types of animals have shown it may be a carcinogen. It sound terrifying until you find out that coffee has quite a high degree of acrylamide in it. When we heat or bake foods acrylamide can be naturally formed. It may not be a "good" thing, but it already exists in most of our diets already. Acrylamide also readily breaks down in the soil to ammonia, which is a fertilizer, so I have no concerns about a build-up.

I admit it would be better if everything was just totally safe but doesn't it feel like everything gives you cancer these days?

[TrysHard]

I would be interested to hear if there's a great difference between using vermiculite and perlite in your 'recipe'?

I bought both to try them - I would say Vermiculite for veg containers deffo - for seeds not sure yet.