Soil magnesium deficiency and Epsom Salts

Does anyone here have any info about the quantity to use and how to apply Epsom Salts to fix insufficient magnesium in the soil?

I've Googled, emailed the NZ importer (no reply a week later) and tried to find a website in Epsom, England about the salts. All I've ever found is "just dig in a few handfuls" which is far too imprecise for me. I'm well aware that too much of something can be just as bad as too little.

Two summers back I got a lot of wilting on my tomatoes which I just thought was the consequences of the local tough environment on the Manawatu coast in the roaring forties with early frosts, very hot summer sun, strong westerlies laden with salt, and a natural "soil" of just grey beach sand, so everything I grow plants in is imported and the large amount of compost I make probably repeats any deficiencies.

Last summer I lost all my tomatoes when they were just starting to fruit, so I checked the exact type of wilting and sure enough, it's magnesium deficiency. None of my gardening books give useful info about fixing magnesium deficiency either, so I don't know what's safe to do about it.

I have two packets of Epsom Salts sitting waiting to be used, and I swallow a dissolved pinch of them now and then to prevent old-fart's leg cramps at four in the morning, which are very painful! Nowadays there is no mention of Epsom Salts being a powerful laxative, as I found in my childhood in the 1950s, :-( and they are just sold as bath salts.

Any advice about anything other than Epsom Salts would also be appreciated.

This may help
https://bestplants.com/epsom-salt-garden-cheats/

Be aware it's a fix, not a permanent cure.
It's probably lacking so Dolomite lime will fix it more permanently.

You could join the Facebook group, NZ vege gardeners and they have many helpful tips about this sort of thing including one persons experiment with crushing egg shells ad leaving in water to see if it helped and it fixed the problem (ie low in calcium). Also someone measured the amounts of nutrients in a similiar brew indicating lots of calcium. Other hints last week have been home made liquid fertilisers made with weeds such as comfrey and nettles or seaweed. Epsom salts doesn't seem to be something you are going to OD your plants with hence the loose application rates. I also had wondered about this. If you can't kill it by putting a spoonful under the roots then you aren't likely to!

Thanks all three posters, it's good to go from ignorant to knowing something useful in 24 hours.

For some reason when I Googled the subject the Best Plants site didn't come up, or was perhaps buried among many others.

I'll look into dolomite lime -- have been using plain lime.

When I saw that webpage mention a tablespoon of Epsom Salts per seedling I first thought they meant tree seedlings, not vegetables. Obviously I need to treat all of my soil -- I grow mostly salad veges.

Do garden centres sell Epsom Salts in bulk? I've never noticed it.

You can buy Epsom salts in bigger bags at places like pgg wrightsons or saddlery warehouse. Horse people use lots of it.

Epson salt is a very soluble form of magnesium (magnesium sulphate) which means it is rapidly available to plants' roots but also very readily leached out of the soil by rain or watering.

Using dolomite (calcium magnesium carbonate - CaMg(CO3)2) will supply your soil with a far longer lasting and stable form of magnesium.

You should however be advised to have your soil analyzed before adding individual elements such as magnesium as the symptoms you are observing may be due to deficiencies (or excesses) of other elements, or even a problem with soil pH. For example an excess of one nutrient can prevent uptake of another so a balance must be maintained. For example in your case the sodium in your "salt laden winds" may be impacting on magnesium uptake, particularly if you include (salty) seaweed in your compost.

If you are growing in commercial quantities soil (and possibly foliar) testing should be a regular feature in order to optimise production and prevent wasted inputs. Also be aware that the current wet and cloudy weather will have an effect on nutrient uptake of many crops.

Thanks strathview -- I was intending to phone around garden places tomorrow (oops, today) about finding bulk Epsom Salts, but didn't know about horse people using it.

Harm-less -- Thank you too. I never felt good about using local seaweed and salt content might be why. Other locals have used it with success for some flowers. Re your last sentence, yes, seedlings I transplanted a month ago were hardly any bigger after three weeks. Have just started growing the last few days.

I also have pine trees on my boundary adjacent to the vege garden, and they drop heaps of acidic pine needles onto part of my garden where growth is now poor, and after finding their roots had penetrated up to 5 metres under my garden I dug and cut for a week to get rid of them. Couldn't figure what I had done to become such a lousy gardener over the last few summers, and the problem was those roots sucking out the nutrition. But the pine trees looked really good!

Mind you, for anyone who grows carrots, nearby pine forests are an excellent help. I had trouble growing carrots in clay in Wellington and would struggle to get the puny things out of the ground, but here on the coast my old dad had excellent, big carrots and I just had to reach down, jiggle their tops around a little, and lift them out. I asked him his secret, and this was it:--

Grab a sack and a garden fork, go down to the forest, and stomp around until you reach a spongy area, usually in the hollows. Whip all the pine needles off the top and take home all the rotten stuff underneath, but replace the pine needles so they can rot down. Put the rotten stuff in trenches with a thin layer of soil on top, and sow your carrot seeds in that.

Boy, did that work back in Wellington's clay. Apparently the rotten pine-needle mould has lost a lot of its acidity but still has enough that carrots love it. Plus it stays pretty much the same throughout the life of a season's carrots, so it's quite loose around them. And it retains water.

I've just Googled "soil analysis domain:.nz" and got heaps of hits. Any recommendations as to who to pick? Are home kits any good? I bought an acidity test kit once and it was pretty basic, but told me what I needed to know.

I narrowed results by adding "home garden".

Qlabs.co.nz:--
"Home Garden Soil Testing $50 + GST (Calcium, Magnesium, Potassium, Sodium, pH, Phosphorus)"

Is that the best sort of test and a good price?