Mesquite natural history and bean pod harvest

A Sonoran Desert Mesquite Bosque made up of Velvet Mesquite (Prosopis velutina).

Starting towards the end of June and through mid-August or so, Mesquite (Prosopis sp.) bean pods are ripe for harvesting in and around the Sonoran Desert.  Once the pods are tan colored and dry they are ripe.  The pods have two parts; the seed portion and the pod.  Both can be edible.  The seed portion is a bean which is as hard as a rock. By itself it is not digestible unless it is ground up.  The pod part is edible and has an earthy sweet taste.  All kinds of desert animals such as deer, cows, javelina, rats, and others consume the bean pod along with the bean.  The pod provides nutrition for the animal but the bean passes unharmed through the animal.  As the bean is passing through the digestive tract is absorbs moisture, may be partially scarified, and is finally deposited in a warm moist pile of dung.  All of this can greatly aid seed germination and survival of the seedling.  Animals also provide the extra bonus of carrying the seeds to new locations as they pass through the digestive tracts.

Velvet Mesquite bean pods ripe for harvesting mid-June in the Sonoran Desert.

While none of this is pretty, it is pretty darn effective.  In the absence of fire and/or other biological controls that scientists don't exactly understand, this method of seed transportation and deposition has at least partially caused the spread of mesquite trees all over the southwest.  Mesquites were once widely interspersed in desert grasslands and limited to wet areas where they would form dense "forests" called bosques.  In the present day they have invaded desert grasslands, often forming nearly impenetrable thickets.  Once these thickets are established, only fire, herbicides, or mechanical removal of them can return the grassland to an open state.  These treatments, particularly fire, are most effective before the mesquites become too large.  It is extremely difficult, if not nearly impossible, to remove an established mesquite thicket.

When the pods are dry and tan they are also ready for people to harvest them for eating.  The whole process can be quite easy for someone willing to brave the heat.  Simply find a tree with tan dry pods and pull them off the tree.  Some trees will produce sweeter tasting pods then others.  Simply break some pods and chew on them to see if you like the taste or not.  Collect pods from trees that taste favorable to you.  Mesquite pod collecting is legal on certain public lands such as Forest Service and BLM lands but not on National Park or preserve lands.  Private land is legal if you have permission.  Make sure you know where you are and the legality of collecting at that location.

Once you have collected all the pods you want, take them home and dry them out in the oven.  Set the oven as low as possible, 150 degrees is a good temperature.  Simply bake the pods until they are perfectly dry.  This is essential, the bean pod must be absolutely dried to the point where they can be very crisply broken.  If they are not crispy dry, the pods will gum-up and clog whatever you choose to grind them up with.  Also, drying the pods in the oven kills the often abundant insect life that likes to feed on them.  You can eat these bugs for the added protein, but I prefer not to, and don't suggest you do...  Next, you must grind-up the whole pods somehow.  Either a blender or coffee grinder will work well.  Simply place the pods in the blender or grinder and turn it on.  This should yield a powder mixed with pulp.  Lastly, the pulp and flour must be separated out from one another by using a mesh sieve.  The pulp, which will contain seeds if you used a blender, cannot be eaten.  Coffee grinders grind-up the beans making them edible.  The flour that comes through the sieve can be eaten.

Mesquite flour

Mesquite flour has an earthy-honey-desert-like taste and is great to add into bread, cornbread, and pancakes.  You can take any recipe you already have and simply add a quarter to a half cup or so of mesquite flour.  It also is great as a meat seasoning.  The flour can be rather dense and strong flavored so limit how much you add to your recipes.  Mesquite can also have a semi-bitter aftertaste, so limit how much you add to your recipes.  I especially like it in cornbread and as a meat seasoning.  Whatever you decide, play around with it and see what works and tastes best.  And let me know how it all works out for you!

Below are two websites with many good mesquite recipes:
http://www.casadefruta.com/mesquite-recipes.php
http://www.louqart.com/mesquite_recipes.html

Garden update (a little late)

Phoenix College garden

I know my garden economics update is long over due, but better late than never...  Things have been extremely productive in the garden lately with the nice weather we had through May and the beginning of June.  It isn't until temperatures start hitting about 110 degrees that things start suffering.  If we consistently stay below around 105 for the high everything seems to do quite well.  Some things like eggplant, some chili's, okra, and Armenian Cucumbers really don't care though.  One of my rules of thumb for Armenian Cucumbers is to plant only one every summer being it spreads and produces throughout the garden with vengeance!  Once it gets going its hard to stop.  June has been dry as usual.  Now with daytime highs consistently over 110 it can be difficult keeping the garden going.  The high temperatures will last until we get some rain and the medium term forecast makes it look like the monsoon rains may come in the next week or so.  But rain in the desert can be quite elusive.

Here are the stats:  All prices are based on local Fry's or Sprouts organic produce.
College garden
Tomatoes 13lbs. 6oz., $40 ($2.99/lbs.)
Green onions 1lbs. $4.72 (0.59/lbs.)
Green beans 2lbs. 14oz., $8.60 ($2.99/lbs.)
Garlic 7lbs. 4oz., $23.25 (0.75/head)
Summer squash 2lbs., $5.98 ($2.99/lbs.)
Total hours: 6
Total calories burned: 1836
Calories produced: 6035
Net calories:  4199
$ spent: $0.00
$ produced: $82.55
Net $: $82.55

Home Garden
Zucchini 9lbs. 9oz., $28.59 ($2.99/lbs.)
Green onions  8oz., $2.36 ($0.59/2oz bunch),
Chard  1lbs. 4oz., $6.25 ($2.50/8oz bunch)
Carrots  3lbs 1oz., $3.04 ($0.99/lbs.)
Basil 7oz., $10.47 ($1.89/2oz bunch)
Tomatoes 12lbs. 5oz., $28.59 ($2.99/lbs.)
Peaches 2lbs., $3.98 ($1.99/lbs.)

Cucumbers 1lbs. 8oz., $3.75 ($2.50/lbs.)
Eggplant 2lbs. 4oz., $4.46 ($1.99/lbs.)
Green beans 1lbs., $2.99 ($2.99/lbs.)
Summer squash 9lbs. 3oz., $22.97 ($2.50/lbs.)
Total hours: 6
Total calories burned: 1836
Calories produced: 5182
Net calories: 3346
$ spent: $0.00
$ produced: $117.45
Net $:  $117.45

Totals since October 2010
College garden:  
$ Totals: $111.08+$82.55=193.63
Total hours worked: 24.75
Calorie totals:4151+4199=8350

Home
$ Totals: $103.67+$117.45=221.12
Hours worked: 25.25
Calorie totals:1708+5054


The end of June through the middle of August can be really tough on the garden.  The sooner we get the monsoon rains and the more of them we get the better.  Without the monsoon rain the heat and dry weather can virtually destroy everything in the garden (except for okra, Armenian cucumbers, and eggplant of course!).  

Saguaro natural history and fruit harvesting

Saguaro fruits ripening on the ends of some saguaro arms. 

As mentioned in a previous post, the month of June can be pretty slow in the month of June.  Slow that is until the Saguaro (Carnegiea gigantea) fruits ripen and begin bursting open.  If it wasn't for this fruit the normally 110 plus degree temperatures and scorching sun would keep everything wishing they were in the mountains or hibernating somewhere far away.  Ripe Saguaro fruit wake many animals up from the lazy month of June. Due to these fruits these organisms are more willing to brave the extreme heat and will often hyper-actively gorge themselves for several weeks.  These juicy fruits are not simply an abundant food source, they are also an abundant water source during the hottest driest time of year.  When the fruit is ripe it bursts open, exposing the edible pulp to the outside world.  Bugs of all types will swarm around these fruits, eating the sweet contents.  Even ants will climb to the top to find the food.  Many types of birds will also go from Saguaro to Saguaro eating their fill of fruit or bugs.  Much of the fruit also falls to the ground where rodents, deer, and javelina can consume them.  As you can probably see, without the Saguaro not nearly as many animals could inhabit the Sonoran Desert through the summer.  This is part of the reason Saguaros are considered "keystone" species.  Keystone species are organisms that play a critical role in determining ecosystem structure and what organisms live there.

Dove sitting atop a Saguaro consuming ripe fruit.

Conveniently and purposely, Saguaro fruit ripening is timed only a few weeks prior to the summer monsoon rainy season.  Saguaro fruit pulp is loaded with tiny black round seeds that are eaten up by anything that eats the fruit.  Oddly, this is actually a very good thing.  As long as the seeds are not chewed they will pass through the entire digestive tract unharmed.  In-fact, partial digestion of the seed coat may actually help seed germination.  Being saguaro fruits are so high in the air, birds are the primary consumers and carrier of the seeds.  When undigested seeds pass unharmed through the digestive tract, they are often deposited under a bush or small tree such as the Palo Verde (Parkinsonia microphylla) that the bird perched in.  These nurse plants (the bush or tree) create an ideal microclimate with increased moisture and nutrients, and decreased sun and temperature.  This microclimate is ideal for the saguaro seed to germinate and grow to adulthood.  Even so, only a tiny fraction of seed actually germinate, and an even tinier fraction grow to maturity.  And by tiny fractions I mean tiny fractions of one percent, the remaining seeds or seedlings die in the unforgiving desert environment.  This is absolutely normal, and for a Saguaro population to maintain itself only one Saguaro needs to reach maturity for each Saguaro already in existence.  That is, each plant only needs to produce one out of millions of seeds that germinates and grows to maturity.  To help ensure germination of these seeds the plant produces all its seeds every year just before the summer rains.

Two Saguaro fruits.  The black part at the top of the fruits in the old flower.  

Humans also have been active Saguaro fruit harvesters and consumers for many millenniums.  The process is quite easy if you have a long stick, 10 foot or so, and are willing to brave the heat.  In Arizona there is no law that I know of that prohibits non-commercial fruit harvesting, but the laws are obscure.  To be safe, harvest with someone, or an organization that has a permit, or on private land.  Also don't harvest very much.  Land managers have told me it is OK to do within reason.  It is however illegal to collect from a crested saguaro.  According to the laws, as long as you are not damaging or removing the plant it is "legal", again the law is obscure and incomplete when it comes to fruit harvesting.  But again, collect with an organization with a permit or on private land, do not harm the plant, and limit how much you collect.

Saguaro fruit cut in half.  The soft red pulp in the middle is what can be eaten.  The green and white wall should not be eaten.

Saguaro fruit is collected by knocking the fruit off the cactus with a long stick and then picking the fruit up off of the ground.  If you want to, you can try catching the fruit in a bag or basket.  Fruit harvesting is best done early in the morning before the scorching sun and 110 plus degree temperatures roast you.  Once a fruit is harvested simply cut it in half and scoop out the soft pulp and eat it.  Do not eat the surrounding wall of the fruit, it contains slightly toxic substances in it and does not taste good at all.  It is extremely good and refreshing in the summer heat.  Native Americans have also dried the pulp in the sun to make a sort of fruit leather.

The Palo Verde: foraging and life history

Some Palo Verde bean pods ready to have their green beans removed and eaten.

While June in the Sonoran Desert may be oppressively hot and dry, there is an abundance of food available to the forager.  One of these foods comes from the Palo Verde (Parkinsonia microphylla).   Possibly the most common tree of the Sonoran Desert, it flowers in April and May, and produces seed by the end of June.  The seed is ready just weeks before summer monsoon rains which usually start mid-July or so.  Freshly shed seeds readily germinate in the hot rains of late July and August.  While a lot of desert plant seeds require a decent amount of rain to germinate, Palo Verdes don't require much rain at all, maybe a half inch or so.  Instead of depending on one single large rainfall event for germination, rather germinate as soon as it is wet and hot, then hope more rain falls in the coming days and weeks so they can become established.  If more rain doesn't come after germination, the seedling unfortunately dies.  Death due to lack of water is a cruel reality in the desert.  Hopefully seed produced next year will be able to grow into established trees with sufficient rainfall.  If you think about it though, each plant only has to produce one established offspring to maintain the population, and that means millions of seeds and seedlings that die every year and only a handful of seedlings that survive to maturity.  This is absolutely normal, keeps the population stable and prevents it from literally taking over the world!  So foraging has little if any effect of the success of this species.

Palo Verde trees growing along a dry wash.

Being the Palo Verde bean is almost as hard as a rock, it is indigestible.  Deer and javelina will still eat the beans but not digest them, instead they will simply pass though the animal unharmed.  Amazingly, passing though an animals digestive tract may actually aid seed germination and deposit it in an ideal location.  For us humans however, we need to eat the beans while they are still green or risk breaking our teeth.  The process of foraging Palo Verde beans is quite easy.  Mid-June or so, simply find some Palo Verde trees that have seed pods.  Pick pods off the tree that are green to tan colored but have green seeds inside.  Its pretty easy to collect a lot of pods from a few trees.  Once you have some pods remove the green beans from the pods.  This can take awhile.  These are the edible portion of the bean pod and taste somewhat like a mild green bean.  They can be eaten raw or cooked.  I have heard of other people eating the entire green pod early in the month of June.  I however have found the green pod to be way too stringy and chewy to eat.  I also suppose the rock hard seeds could be eaten if they were soaked and cooked, but I haven't tried this before.

The green Palo Verde beans removed from bean pods like in the picture at top.

For now anyway, I am sticking to eating the green beans once they are removed from the pod.

June in the Sonoran Desert

A hot dry June Sonoran Desert landscape.

There are many words you can use to describe June in the Sonoran Desert.  Hot, dry, dusty, very hot, scorching sun, cloudless, and.. did I mention hot.  Between the Saguaro bloom at the end of May and when the Saguaro fruit finally ripen at the very end of June, not much happens.  Everything seems to get pretty lazy in the intense heat and dryness.  The only real activity seems to happen very early in the morning when temperatures are in the 70's or low 80's.  During this time flocks of doves ride the breezes and other birds and animals can be seen sneaking in a little activity before the sun gets hot around mid morning.  Fortunately, this summer hasn't been quite as hot as it can be, highs have been around 100 and 103 every day lately.  Often we can have highs round 110 this time of year with lows around 80.  Those temperatures are probably coming in the next few weeks.

Palo Verde bean pods ready to have the beans removed and eaten.

June can be a rather interesting month though for the hunter gatherer, if not for the rest of desert life.  During mid-June Palo Verde (Parkinsonia microphylla) beans are ripe for eating.  Mesquite (Prosopis sp.) bean pods are also just beginning to dry out in some locations for harvest.  (I will have a post on these two plant harvests in the next few weeks or so.)  Wolfberry (Lycium sp.), a relative of the Gogi berry, is also ripe in some locations if a decent amount of rain was received during the spring.  Unfortunately, due to the lack of rain this spring though I haven't found any Wolfberry.  Deer and javelina will eat the Mesquite and Palo Verde beans but none of this really seems to help the bugs and birds out much.  Overall, everything seems to be waiting for the Saguaro fruit to ripen and supply huge quantities of sweet calories and water to the desert.  But not to worry, in a week or two when the summer heat is at its most intense, Saguaro fruit will be available in abundance.  Overall though, I think June makes everything living in the Sonoran Desert wonder why it lives their.

Unripe saguaro fruit

The how and why to determine soil texture

All soil is made up of three different sized particles clay being the smallest, sand being the largest, and silt somewhere in-between.  Different proportions of these particles results in different types of soils with different water holding properties.

Nearly all life on land is dependent on the soil beneath our feet.  For this reason, as a gardener or amateur scientist your ability to become familiar with soil types and textures can become critical.  Things that grow in one soil type will not grow in another soil type.  Or watering one way in one soil type will have completely different results in another soil type.  Even if you look at the lawn in your own back yard you may notice different species of grass growing in different patches, these patches often correspond to different soil types.  Or even patches of lawn where it is difficult to get grass to grow may correspond to a certain type of grass.  In the more natural world different habitats strongly correspond to the different soil types they are found on.  Think about it, if you were able to identify soil types and texture you would be able to explain gardens, habitats, plant growth, and water drainage among other things and amaze all your friends! 

So how can we learn how to explain a soil?  Well first of all, soil is not simply dirt but is a complex mixture of materials most of which are derived from a parent material, typically the rock common to an area.  As I mentioned in a previous blog entry, particles aggregated together to form a rock eventually breakdown (called weathering) into individual particles that will go onto form soil.  These individual rock particles (crystals) come in three different size classes, which determine the texture and properties of a soil.  Clay is the smallest particle size, sand is the largest, and silt is somewhere in-between.  Differing proportions of these three soil particle sizes within soil determines the overall texture of the soil.  While the chart at the top of this entry looks fairly complicated, its actually fairly strait forward; more clay particles in a soil means a clay soil, while more sand in a soil means a more sandy soil. 

Size comparison of sand, silt, and clay.
 

Sand, silt, clay, this is all known as soil texture.  More sandy soils are referred to as having course textures due to the course nature of sand, while clay soils are referred to as having fine texture due to the fine size of clay particles.  Why does this matter?  Well, soil texture determines its capacity for holding water.  And a soils water capacity will determine what grows where and how we should water or amend it to create an ideal plant environment.  Hmm... Apparently you need a dirty brown thumb before you can have a green thumb!

There are two quick and dirty ways for you to determine soil texture and they can be done just about anywhere.  The first is a touch or "ribbon" test.

Soil "ribbon and ball" test
1. Collect about a ping pong ball amount of soil and moisten it with water.
2. Once the soil is moist, try to form it into a ribbon.  If you can form the moist soil into a ribbon you know the soil has a lot of clay in it.  If it will not form a ribbon it has a lot of sand in it.  The stronger the ribbon the more clay the soil has in it.
3. Form the moistened soil into a ball and squeeze it.  The easier the ball breaks apart the more sand the soil has.  The harder it is for it to crack or break apart the more clay the soil has.
4. As you are handling the ribbon and ball note how the soil feels.  Gritty feeling means sand and a smoother feeling means clay.
From these steps you should be able to identify if you have more clay or sand in your soil.

This is a soil ribbon.  If you can form a ribbon like this it means your soil has a lot of clay in it.  If you can't and your ribbon keeps falling apart it means you have a more sandy soil.

Soil settling
1. You will need a clear glass or plastic jar with a lid.  A typical peanut butter jar works well.
2. Collect soil soil, enough to fill the jar up about half way.
3. Dry the soil out and break up all the dirt clods.  You can skip this step if you want but be sure to shake extremely well in step 4 in order to break the clods up.
4. Fill the jar about 90% full with water and shake like crazy, ensuring all clods are broken up and all soil particles are suspended in the water.
5. Shake the jar like crazy,   And when I say crazy I mean crazy, no excuses.   Do this for at least a minute, longer won't hurt.  Then, set the jar down and watch.  The heaviest sand particles will settle out within a minute, silt particles within two hours, and clay particles after that.  You can mark the jar at the top of the sediment mark after 1 minute and two hours to give you these divisions and give you an idea of what proportions of particle sizes the soil is made of.

The above experiments can be found in more depth at: http://cmg.colostate.edu/gardennotes/214.pdf

Now that you have patiently endured some of the theory and practice you are probably wondering, "why the heck is this important?"  As mentioned before soil texture determines what grows where and how you water.  Clay soils hold more water and absorb water slowly.  This is why wetland soils are usually very fine.  Clay soils also hold their water for long periods of time because water sticks to the surface of clay well.  Clay absorbs water slowly though and requires a longer but slower irrigation in the garden because of this.  So in nature clay soils are typically wetter and often associated with wetlands or plants that like moisture.  In the garden or landscape clay soils will also be wetter and require slower irrigation.  Sandy soils however are typically drier and absorb water quickly.  The large particle size of sand makes for a lot of space between particles for water to peculate through very quickly.  This also allows for water to evaporate from sand very quickly also, so sandy soils tend to be drier.  Sandy soils are often associated with dry habitats or plants that prefer drier soils.

So after you test a particular type of soil for sand-silt-clay content you can associate certain plants or habitats with that soil.  You can also assess your garden soil and adjust watering and planting accordingly.  Most garden plants can adapt to most soil conditions but do best in a "loam" soil.  Some plants to prefer sandy or clay soils though.  A loam soil has even amounts of sand, silt, and clay, and as a result it absorbs and holds just the right amount of water and air for plant roots to breath.  I have had several garden of my own, none of which have every been loam.  As a result, I have had to adjust soil texture by adding sand to clay soils, or adding clay to sandy soils, or add organic matter to adjust the water retention or drainage of a soil.

June in the Phoenix College garden

Its June, and its been a pretty nice June for Phoenix.  So far the weather has not been unbearably hot and the nights are pretty nice.  We haven't had temperatures much above 100 at all.  This has made for some great growing conditions, with irrigation of course.  Currently the garden is growing like crazy and producing all kinds of veggies and flowers.  In places the garden appears almost jungle like.  Thought I would share some pictures of what is growing in our garden here.

Artichoke

Not sure what this is.

Sunflower

Sunflower

Coreopsis

Fish chili peppers

Onion flower

Eggplant flower