(I would like to note that I am not a horticulturist but have simply compiled a lot or research and resources and wish to share what I have learned in hope it helps others. As there is a lot of info and resources in this, I have broken this article into 3 pieces and will list all the resources at the end of this part 3)
Just like many living organisms (especially for us women), plants need calcium as well to produce a STRONG structure. Bones in our case, and cell walls for them. Calcium is also important for protein formation and its alkaline pH neutralizes overly acid soil that might prevent uptake of other important elements plants need. Straight calcium is hard for plants to utilize as it is not readily dissolved, and better forms of calcium for uptake include lime, gypsum or seaweed/algae.
Sign of Calcium deficiency include:
-blossom end rot
-curling or yellowing of leaves
-brown tipped leaves
-growing points show damage and die off
-forked root crops
Natural Sources of Calcium:
-Egg shells: better if dried and crushed or powdered ahead (though I rarely do)
-Powdered milk/sour milk/yogurt: Sprinkle powder milk around base of plant or make into liquid form (or use dilute milk or yogurt) and water. Spraying with either reduces powdery mildew because of its lactic acid.
If you have ever noticed your plant going all Prince (Artist Formerly Known As/weird symbol/whatever) on you, aka Purple-y, you’re probably experiencing a magnesium deficiency. Magnesium is needed for chlorophyll formation and when it gets out of whack in a plant, things get a little psychedelic purple… or just yellow, blah. This elements needs to be in balance with calcium so if magnesium is going wrong, your calcium might too.
Sign of Magnesium deficiency include:
-yellowing or yellow spotting of leaves
-poor crop flavor
Natural Sources of Magnesium:
-Epsom salts: (magnesium and sulfur source) There is caution in this, especially about over application of Epsom salts and if you are unaware of the needs of your plants/soil conditions, please research before application
(Cautionary link: http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Myths/Epsom%20salts.pdf)
If we couldn’t get all our plant symptoms all the more mixed up, with yellow leaves being an indicator of EVERYTHING it seems, then plants lacking iron will not surprise you by looking anemic (yellow) too when they are lacking this element. Iron is vital to chlorophyll production and thus, when there is a shortage this deficiency is called chlorosis. One trick to note if your plant has chlorosis is to note if it has green veins. Iron also helps make plant proteins (think of muscles/meat=protein) as well as enables plants to fix nitrogen for use. As fixed elements go, if the pH is too high iron becomes locked up and an alkaline like lime can free it. (I imagine a lime fruit riding in on a horse, wielding a sword to free a laundry device in a tall tower. I know, I’m weird).
Sign of Iron deficiency include:
-yellowing of leaves with green veins
-quick growing plants will show signs of damage first
Natural Sources of Iron:
-Blood: (either in meal form or I have heard that some farmers in the old days would use slaughtered animals’ blood or in ancient times they would water plants with high iron needs by hanging an animal whose throat they slit above such plants. Gruesome, but it works I suppose).
-Some hardwood mulches might leach out iron I’ve read, but I can’t find it confirmed.
The last necessary element for this section I want to mention is sulfur. Proper protein production requires sulfur (it's used in certain bonds to form protein) and a plant that lacks available sulfur will find it difficult to produce new leaves as plant growth hormone regulators need this element to form. Sulfur is linked with iron and can help remedy chlorosis, when sulphates are added.
Sign of Sulfur deficiency (usually only a problem in sandy soils) include:
-even yellowing of leaves especially in new leaves
-slow growth of new leaves
Natural Sources of Sulfur:
-Matches: Only a little is needed and some people swear by burying wood or paper matches with plants or if they think there’s a deficiency.
-Blackstrap molasses: sulfur and trace minerals (great after baking gingerbread or molasses cookies!)
-unfortunately can’t find more ‘natural’ sources… if you can think of any that don’t come in a bag, please tell me!
Next time, on to the tiny and fabulous world of micronutrients and the last part of this set, Soil Nutrition Part 3 of 3: Zinc, Boron, Copper, Manganese (and maybe some Molybdenum!)