I wondered about the need for application of MgSO4, whether some plants (species or cultivars) are just inefficient at transporting magnesium and/or sulfur, or if it is more a question of lacking sufficient water movement within the plant (insufficient light, transpiration ...), which prompts a grower to apply it when pH and soil nutrients are within acceptable ranges? Epsom salts give a greening-up effect, and it may be used for example, added to foliar orchard sprays or a fertilizer drench on a greenhouse crop such as geranium.
What rate? (ounces per gallon, or teaspoons per gallon) Would it make much difference (increasing blossom set) if the soil it's in is within an optimal pH and contains sufficient magnesium and other nutrients?
It's normally 1 tablespoon to a gallon of warm water. Mix throughly and spray the plants. If your ph is optimum and you already have sufficent magnesium in the soil. You should have no problem with blossom set. This is normally recommended when the gardener has less than ideal soil, or sometimes it can "push" the set of fruit in cooler conditions.
In 2007 I ran a bit of a controlled experiment. I had 20 tomato plants (2 of each plant) and carefully sprayed with epson salts one of each plant. The result was zilch, zero. There was no difference between the control and the treated. Like all experiments it would have to be repeated several times to ascertain meaningful results, but for me it was sufficient to forget about epson salts. It does make a violent laxative though.
To true. Do continue with your experiments. Just keep in mind that what won't work for you, may work for me, just because there are so many variables. I've done this "scientific" deal over the years. And lo and behold, if you're using my ground for the experiment, it works......imagine that!
Does epsom salt change pH at all; if so, in which direction? Regarding the scientific trials in which it was of benefit in one experiment and of no consequence in the other: perhaps high potassium levels caused a minor magnesium deficiency in one case; and in the other case this was not so, and the extra magnesium from epsom salt made no difference.
It does not change ph at all. Plants need to absorb the magnesium so they can optimize the absorbtion of calcium. especially tomatoes. And again, you only use this is you need to use it. Your plants will indicate you have a problem, many times it starts with changes to the color of the vines and is certainly something to explore when you have persistant problems with BER in tomatoes.
BER = Blossom end rot? Sorry, I'm more a fruit grower who occasionally plants some vegies (I did sow some 'Bloody Butcher' tomato seeds indoors today).
BER=blossom end rot Ah, I see, then espom salts really wouldn't be particular valuable in the growth of fruit trees. It's my understanding the trace nutritional needs are quite different from what's need to get good veggie crops. Do you a cover crop around your fruit trees?
Experimenting with buckwheat, crimson clover, other annuals that will winterkill. I know someone who puts epsom salts in every orchard spray through the year (including a mix with Calcium Chloride, which is not recommended,) thinks he's clever.
"The science behind the use of Epsom salts is only applicable to intensive crop production in situations where magnesium is known to be deficient in the soil or in the plants." This is from Linda Chalker-Scott, Extension Urban horticulturist at Washington State University http://www.puyallup.wsu.edu/~Linda Chalker-Scott/Horticultural Myths_files/Myths/Epsom salts.pdf Also, from K-State Extension: It seems like there are a number of old wives’ tales for Epsom salts and its power in the garden. For the most part these pass along recommendations provide little benefit. The thought behind Epsom salts is that it provides a source of magnesium for the plant that helps fend off all sorts of problems. The truth is that local soils normally have plenty of this little used nutrient. So the answer is, using Epsom salts will probably not help, but if it makes you feel good about gardening go ahead, it won’t hurt the plants. — Dennis Patton, Johnson County K-State Extension Horticulture Agent
Those statements appear directed towards gardeners, but a perfectly reasonable use of epsom salts - in container gardening - has been overlooked. Soil-less potting media doesn't have much nutrition to sustain plants, so fertilizer is used, and irrigation water can also provide some nutrients, such as calcium, magnesium and sulfur (these are usually absent from water-soluble fertilizers such as Miracle-Gro). Saying that a macronutrient such as Mg is "little used" is inaccurate;this table gives good info regarding macros. Obviously I meant if it is used on the soil, not a foliar treatment. I'll assume the answer stands.
Magnesium deficiency symptoms vary with the species but tend to show up on older leaves. A preventative program works best as once symptoms appear treatments are slow to produce results. Plants need it to make chlorophyll and do other important things. But, as always with nutrient applications, you want to establish a need for it before taking the time and spending the money, and you don't want to overload the plants with it.
First off to change the ph you need to apply a lot. For clay soils using limestone(slow release) you need somewhere around 1-2lbs. per square yard. Epson salts (magnesium sulphate) because being a sulphate the ph would lower. Lime (calcium carbonate) raises the ph bringing the ph closer to neutral being 7 on the scale form 0-14.Saying that as Ron said before all soil may contain different minerals affecting the ph. Have your soil tested in different places in your yard.
