Most home vegetable gardeners have seen somewhere or heard from someone the importance of the N, P, K levels in your soil. These letters represent specific elements and stand for Nitrogen (N), Phosphorus (P) and Potassium (K). If you look on any bag of fertilizer available at your local home or garden center you will see these letters and usually a ratio values right on the bag, bucket or box.
Although, N, P, and K, are considered the big three, they are only a few compared to the many elements and nutrients your plants need in order to grow or thrive. Just like you need all of your vitamins and minerals from A through zinc, a plant requires many nutrients as well.
One specific nutrient it needs, just like humans, is calcium. Calcium in plants is required for proper cell division during plant formation and growth. If your soil lacks calcium the leaves of your plants will look yellow or pale and blossom end rot will occur more frequently. Other signs of calcium deficiency include bad root formation, browning of plants and small vegetable and fruit formations.
If you have been vegetable gardening for sometime then you already know the importance of composting. If you do just simple composting such as burying your food scraps or keeping a compost pile of leaves, twigs and grass clippings and then adding that compost to your soil, then you more than likely already receive ample amounts of calcium. Of course if you are not doing this then you should begin right away. There is nothing better for your soil than adding organic material that will decompose and breakdown into the nutrients your soil needs.
Good sources for calcium beyond composting include calcitic lime, calcium sulfate gypsum, bone meal, soft rock phosphate, calcium carbonate, and for those of you that have fire places, wood ashes. All or most are available at your local home or garden center with some being a lot more pricey than others. So if you are going to put out some money make sure you get a source that also includes other valuable nutrients. Bone meal for instance is a great source for phosphorus as well and by adding bone meal (a mixture of crushed bones) to your soil you are getting two very valuable nutrients for the price of one.
On a side note, although wood ashes are a great source for calcium and a bit of potassium, never ever use ashes from charcoal. These ashes could be toxic to your soil, your plants and the underlying ecosystem that works hard to break down your organic material that you are burying.
If you plan on using a commercial product, make sure you follow the instructions on the container so you do not add too much or not enough. A soil reading with a home soil testing kit comes in very handy so you know exactly how much calcium your soil contains. You can pick one up at your local home or garden center for just a few bucks.