Life of a Cactus Part 1: A Cactus Home

A saguaro cactus in the Sonoran Desert.

So I got a bit carried away with writing about cacti, I think I have at least an eight part series ready to post.  I may be able to add more to that even.  Hopefully its not too boring for anyone because I personally find the existence of the desert cactus quite interesting.  Being the series will be so long I will not post each part in succession, there will be breaks where we have posts of differing subjects.  Hopefully this extended series will spark your interest in cacti!

The Cactus Home

Ask just about anyone why cacti are common desert plants and of course they will tell you it’s because they store water in their stem.  And of course this is true, but it’s only the tip of the iceberg.  Beyond water storage, every part of a cactus is highly adapted to moderately dry desert conditions.  I say moderately dry conditions because extremely dry deserts with say four or fewer inches of rain a year generally do not have many cacti.  Everything needs water, and cacti need slightly more than next to nothing.  Extremely dry deserts are generally barren of nearly all plants, including cacti, except for a few scraggly shrubs.  But even in extremely dry deserts cacti can be found in dry washes, owed simply to the slightly higher concentration of water in these areas after rare flash floods.  Even slightly more than four inches of rain annually, or even double or triple that, is still very dry.  Under these conditions everything seems to work against water storage for the cactus.  Even so, this is where the cactus works best. 

Hedgehog cactus growing in the Sonoran Desert.

Not only are deserts excruciatingly dry due to lack of rain, but many are also excruciatingly hot.  While not all deserts are hot, most cacti find their home in the hot deserts of North and South America.  Dryness only contributes to this heat.  Moisture and humidity work to stabilize temperatures, and therefore prevent extreme highs.  So called desert dry-heat is often oven like due to lack of humidity.  But even in the shade this extreme temperature can be tolerable.  Unfortunately, there is not a lot of shade to spare in the desert.  In more humid environments atmospheric moisture filters large amounts of sun from ever reaching the ground, thus shielding from harsh sun rays and extreme temperatures.  Dry desert atmospheres result in a sun intensity that can be as much as three times greater than humid temperate regions.  So from the simple lack of rain, temperature increases more, robbing even more moisture from everything in the environment.  The resulting low humidity also aids scorching sunlight which again contributes to higher temperatures and lost moisture.  Simply put, dry conditions make it even hotter, which makes it even dryer.  Cacti can thrive under these conditions when most other plants either go dormant or die.

The next part of this series will cover how cacti roots are adapted to the dry desert.

Plant Galls: Where Do They Come From?

Creosote gall.

This morning while hiking I came across a few odd masses of leaves growing on Creosote Bush.  These masses of leaves are technically galls caused by the Creosote Gall Midge.  This insect lays an egg or eggs along with fungal spores in part of a Creosote Bush.  There are 15 species of the Creosote Gall Midge, each specializes in laying their eggs in a specific location on the bush.  Some specialize in laying the egg and forming galls in the leaves, others on stems, others buds or flowers and so on.  Each species also does this only at specific times of the year.  When the fungus begins to grow it forms a gall on the Creosote.  Later, the midge eggs hatch and the larva begin eating the fungus inside of the gall.  Once mature, the larva eat their way out of the gall and morph into adult insects.  Once adults, the whole process is of laying eggs with fungal spores in the Creosote begins again. 

Galls are not unique to Creosote.  In-fact they are quite common, especially among oak species.  Gall wasps actually specialize in forming galls, most often on oak leaves.  Gall formation almost always is part of the reproductive life cycle of these wasps.  There are well over 1000 species of Gall Wasps, each individual species specializing in forming galls on one specific plant species.  These galls are often quite unusual looking, sometimes looking even Christmas ornament like.  Below are a few pictures of galls.

Simple and Effective SNAP Hydroponics

Historically hydroponics has been touted as a feasible way of growing foods in third world countries.  Unfortunately, this has not proven to be the case.  The expensive start-up cost along with electricity requirements for water circulation have proven to be extreme hindrances in poor countries.  Hydroponics has been proven though to be an effective space saver and can productively grow lots of food in a small amount of space.  Hydroponics simply is growing plants in a soil-less environment and giving plants the nutrition they need through exposure of the roots to water that contains fertilizer in it.  Recently, a new low tech hydroponics system that overcomes these historical failures was developed in the Philippines.  In its short history it has already proven itself as extremely effective and is transforming communities in the Philippines by providing a safe and inexpensive food source.  It also has allowed communities to generate new streams of income by selling food grown in their system.  The system is known as the Simple Nutrient Addition Program (SNAP).  It uses a reservoir for the nutrient solution to sit in and a cover for the reservoir with pot sized holes in it.  Plants grown in pots or small baskets are stock in the reservoir cover holes and the roots hung down into the nutrient solution.  Extremely simple, easy, and inexpensive yet very effective.  This is so cheap and easy that I am highly considering making my own system in the near future.

Here is a blog with some good basic information on the SNAP system:  http://hydroponics-snap.blogspot.com/