Plant Knowledge to Make You a Better Grower – Plant Growth

Good growers are observant, and learn everything they can about the plants they grow.  There is an incredible amount of plant diversity, and as more and more people grow indoors and out, the types and varieties of plants that people will grow will increase.  There are certain aspects of plants that are the same for all plants.  Larger plants are usually termed vascular plants, because like us, they have veins that move water, nutrients and waste products around the plant.  Mosses are examples of plants that do not have veins.  The lack of veins means that non-vascular plants are limited in size because water has to diffuse through the plant to get to all the living cells.

Vascular plants only grow in certain areas called meristems.   The meristems are areas where cells divide, one cell splits into two cells, one of the cells can become specialized into a root, stem, leaf, or vein tissue, the other can be divide again forming another specialized cell.  Meristem cells act like stem cells in animals. 

Primary growth is how plants get taller.  This occurs in the apical meristem.  The apical meristem for most plants is at the top of the plant, so most plants grow from the top.  Plants do not grow like you and me, if we grew like plants, we'd only grow from the head up.  An exception to this is grass.  Grasses are one of the most widespread plants, found on 6 continents because they grow from the bottom.  This means that grazing and mowing do not damage the apical meristem, and the grass can grow back.  How well would a rose or oak tree do if you mowed it each week like a yard?  ** Here is the take away message** Since the tops of your plants are where new growth will occur, make sure you do not burn the tops of your plants with lights.  This is one of the most important areas of the plant so you want to protect it.  To do this you want to take the temperature of your plants at the tops.  It is in the tops of your plants where most of the metabolic activity is taking place, so you want the temperature and humidity to be optimal at the tops.  I use a thermometer with a separate cord and I put it at the top of the grow area, where it is usually hottest, and I hang the secondary cord down and lay it on the stem at the top of my plants so I know what the temperature is at the plant tops.  Most plants do well with temperatures in the low 80’s, and some people say upper 70’s gives even better growth.  You can figure that out for yourself with your plants in your grow area.

Woody plants get thicker by secondary growth.  Secondary growth or thickness occurs in lateral meristems.  This is a tube like area on the stems were cells divide outward increasing the girth of the plant.  I will be talking about plant organs in future posts, leaves, stems, roots and flowers/fruits.  Until then….

Good Growing,
Dr. E.R. Myers

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