Sunday, September 12, 2010

How to Grow: Taro

Taro is a common name for a wide range of plants under the family Araceae. There are many species of plants that are hosts to the name, and there are plenty of species within the family that are edible. The most commonly used species for consumption is the Colocasia esculenta. The leaves, stems and roots of taro are a staple crop in many regions worldwide, especially Asia.

Taro leaves are indeed considered "Toxic" when uncooked. This is due to crystal compounds that occur naturally in the leaves and stems of taro. These crystals are shaped like small needles and are highly irritating. Consumption of raw taro is a mistake that one will make only once. I have made the mistake myself, upon eating about half of a taro leaf I experienced an itch in my mouth that lead to an extremely painful swelling in my esophagus. Cooking of the taro will reduce the crystal chemicals to a safe level and improve the taste and texture of the plant. Taro is popular in many dishes worldwide; It is commonly prepared in stews and stir-fries. Due to the crystal compounds, leaves (which have a high concentration of these) are considered a "last-resort" food in many regions and is only consumed if there is a food shortage.

Ornamental Uses:
Strictly ornamental varieties of Elephant Ear exist under the Caladium genus with brightly colored, usually pink, leaves. Many species from the Colocasia and Xanthosoma genera are also popular ornamental plants. Variations occur on many of these ornamental species, such as especially elongated leaves. Many include variegations exhibiting beautiful stripes and splashes of color.

Areas for cultivation:
Most Taro/Elephant Ear plants are considered tropical, thus they are sensitive to frost. The majority of these plants need to be grown in zones 10-11 with warm temperatures and a moist climate. There are some ornamental elephant ears that are exceptions and can easily grow in lower zones. Wherever taro is being cultivated, the soil must be light and moisture retentive. At the same time the soil should be well draining as to not waterlog the tubers. If you live in an area with unsuitable conditions for taro, you can always grow it indoors or in a greenhouse.

How to Grow Taro/Elephant Ear:
These plants are easily cultivated by tubers, thick potato-like roots. First you must obtain some of these tubers which can sometimes be found in grocery stores. Depending on the species of Taro these tubers will look very different. Some will be smooth and round, others will be rough with root-like fibers. Growing this plant is as simple as placing the tuber in fertile soil and adding water. You can even cut the tuber into sections to multiply your crop. Within the first week of planting the tubers you should notice a small green stem poking through the soil, this will be the first leaf. Over time the plant will develop into a thick bush and grow to a height of a foot to more than 6 feet (depending on the species). As the plant develops it will send off more shoots, leaves, and tubers allowing you to gradually harvest without harming the plant. Industrial fertilizers should not be necessary for growing Taro, instead apply rich manures or compost to the top soil. If all goes well Taro can be harvested in less than a year.

This is one of my elephant ears of an unknown species/genus. It is different from the rest of my taro plants in that it's leaves are shiny and feel like plastic.
Here you can see the base of the same taro plant. Each stems comes from a single larger stem that keeps sending off shoots. A baby shoot can be seen in the left of the picture. These usually come up straight from the tuber below the soil.

Here is another one of my taro plants of a different species. You can clearly see the difference in growth habits. This plant is also growing from a single base stem but is much taller.

This is the base of the last taro plant. You can see more shoots growing from the base of the main stem. This is common in taro plants and contributes to the thick growth habits.

A more developed Taro plant exhibits what looks like many different plants in the same container. This is because as the plant grows, it sends off new tubers (just like a potato), each of the tubers then has the potential to send off more shoots.

This is a cassava tuber that I purchased at a local special foods grocery store. It was mislabeled as "giant taro root" without a species or genus. This is sometimes the case when buying imported agricultural products, but it certainly makes for a good surprise!

Friday, August 6, 2010

Aqua Caliente Regional Park (Arizona)

The Aqua Caliente park is a hidden treasure found near the city limits of Tucson, Arizona. It's a hard place to find, especially as there are few, if any road signs indicating where the park is located. It opens at 7AM and closes by sunset - there is no entrance fee. It's a quiet place with few visitors and a lot of wildlife, making it a truly unique location. The most interesting aspect of the park is it's hot water spring from which water flows to fill numerous lakes and ponds. It's a tropical oasis in an environment deprived of water. The park is 101 acres of plants and animals, while on my visit I saw deer, turtles, rabbits, hawks, yellow finches, ducks, and countless species of fish. The park also sports a diverse collection of plants, many types of cacti and palms as well as some non-native species.

First impressions: The natural spring allows for dense vegetation and thick grass. This is a great place to sit back and read a book, or to have a family picnic.

This is the actual spring, it is very small but supplies enough water to fill many large bodies of water.

The runoff from the spring is walled in by a thick wall of palm trees on both sides. This stream continues for about 100 feet until it empties into the main lake. Even in this stream I was fortunate enough to spot exotically colored fish.
This is where the spring empties into the lake, but the full view is limited by the tall reeds.

A desert island in the middle of the main lake. Ducks and turtles can be seen sitting in the shade to take a break from the 100F+ temperatures.

There are many species of plants that can be seen in this photograph. This is because the shade and abundance of water allows for a wider range of plants to succeed.

I was very surprised to find a fig tree growing, although it isn't native, it is doing quite well and even has some figs on it.

One of the main attractions is this mesquite tree. It is estimated to be over 200 years old and is a spectacle to even native Arizonians whom are thoroughly accustomed to the mesquite tree. It will produce yellow bean pods which are sugary and edible.

There are a lot of citrus trees too, each with hundreds of unripe fruits. This one is a lime tree.

Nearing the outskirts of the park I spotted this abandoned dam. The tall plants you can see in the right half of the picture are native sunflowers.

Deer are also an occasional sight in the park, like this one munching away at a mesquite tree. 
The second lake has a lot less water in it but still gave some great views.

This cacti is a late bloomer. While most barrel cactus has fruit by this time, this one had just started to flower.

Some views near the spring are very reminiscent of a college campus, minus all of the people.

A view from the outside-in is a sobering reminder that this is a desert, not a tropical getaway.

Friday, July 16, 2010

Costa Rica

My mother recently went on a trip to Costa Rica and brought back a wealth of pictures. The following are pictures that I thought were beautiful and interesting.

This is a picture of a Cacao tree (Theobroma cacao). The pods have a range of colors, these purple pods aren't quite ripe yet. The Cacao pods are the source of chocolate.

Bananas are grown all over central and south America, but few are grown for their ornamental value, like this pink banana flower.

This is a picture from the Else Kientzler Botanical Gardens in Sarchi Norte, Costa Rica.

This is a vanilla orchid vining around two host trees. Typically vanilla farmers cultivate it on host trees that give shade and height allowing the vanilla to climb and flourish.

Ornamental plant farms are common in Costa Rica. They grow plants for genetic research for the creation of new ornamentals, and they grow ornamentals for export. This farm uses a type of terracing to allow for maximum land usage and reduced erosion.

Scenic waterfalls like this are abundant in the dense mountain forests.

Due to high humidity and warm conditions epiphites like these grow on nearly every tree.

Wednesday, July 7, 2010

How to: Propagate Dragonfruit by cuttings

The dragonfruit (aka Pitaya) comes from a variety of species, the most common being the Hylocereus undatus (red pitaya). These cacti are considered to be epiphytic meaning that they can survive on the nutrients and moisture in the air yet they usually still have roots anchoring them to soil. Of all the tropical plants that I am currently growing, the Pitaya is by far the most tolerant to excessive temperatures and brief periods of drought making this a great candidate for desert greenhouse growers like myself. Due to the dragonfruit's long and often unpredictable germination periods propagation by cutting is a no brainer.

Before you start: It is best to do this in warm/moist summer months as this speeds the propagation. Also, don't cut off too much from the parent plant as this will put stress on the plant that may jeopardize its health.

1: Start with a long segment of cactus that can easily be cut into 3-5 sections. Be sure that it is at least a foot long. Try to look for segments that are relatively new but not still growing. I just use scissors to cut the segments into sections that are 3-6 inches long.
2: (optional) Apply a fungicide to the cut ends of each section and place them somewhere relatively dry. This helps deter infections and mold. Note that this step doesn't have to be done but helps with the odds of survival.

3: The next step is to "cure" the cuttings. This allows the cut parts of the cactus to dry out and seal the wound. This is most important in preventing disease and mold from killing the cuttings. I know from experience that cuttings can survive without being cured but it is still a good idea. Cure time should be anywhere from 1-5 days (just wait until the cut ends heal over and turn a little white).

4: Place each cut section in a light soil mix. I suggest mixing some vermiculite and perlite with an average potting soil. Be weary of orientation, each section should be placed in the same direction it was on the plant (don't place them upside down). Each section needs to be planted about 1-2 inches into the soil.
5: Water daily unless the soil is still moist, allow for it to dry out a little. The first thing you might see are roots growing out of the section, this is a good sign of success. These aerial roots will gather nutrients and water from the air, as well as anchor the plant to the soil.
If the propagation was successful a new shoot will emerge. This usually takes between a week to a few months depending on the time of year. Use fertilizer sparingly until they are a year old. Also remember to shield these plants from freezing temperatures.

Within a year the dragonfruit should have numerous shoots coming from the original cutting. These can be heavy and they often go astray so using a trellis or a stake is a good idea to keep the plant upright. In as early as two years you can expect beautiful flowers and delicious dragonfruits. In favorable conditions, a dragonfruit plant grown from a cutting will flower and bear fruit within a couple of years. These night blooming flowers can be elusive to spot during full bloom, but if successfully pollinated the flower will wilt and fall off leaving a developing fruit on the vine. The fruit will become ripe in about a month after pollination.

Friday, June 18, 2010

Dwarf Barbados Cherry

The Dwarf Barbados Cherry (Malphigia punicifolia) is a popular choice for use as a bonsai. This is mainly due to the plant's extremely small size. Aside from use as a Bonsai, the Barbados Cherry is great as an indoor/outdoor container plant. With the ability to withstand 25F temperatures, this plant is quite versatile and will do well in a greenhouse, indoors and outdoors (with mild winters). The light requirements of the Dwarf Cherry are moderate, allowing it to grow in partial shade or even indoors. It's demand for water is high and it shouldn't be allowed to dry out for extended periods of time. I recommend using a well draining soil and watering it often, especially when in bloom or fruiting.

The plant:
The Barbados Cherry (Malpighia emarginata) is a "grown up" version of the Dwarf Barbados Cherry. The plants look very similar in their leaf structures, flowers and fruits, the only difference is that the Barbados Cherry can reach heights of over 20ft while it's miniature counterpart remains at a mere 2-4 feet tall at maximum. The other difference is in popularity, the Barbados Cherry is commonly referred to as an Acerola and has remained very popular in its native tropics. On the other hand, the Dwarf Barbados Cherry is not as popular and remains in the shadows to most. However, the plant has gained significant support in bonsai communities as an attractive fruit bearing specimen.

The fruit:
Cherries from the M. punicifolia are very small (just over 1cm long) and red when ripening. The taste is rumored to be sweet in some varieties, although I find the taste to be rather bland. If I could compare the taste to anything it would probably be a mild tomato. You will find a miniature seed inside of each cherry, but don't get too excited about sprouting it, germination is very difficult with this plant. There are blooming cycles that are activated by numerous factors such as day length, temperature, and water. I am unaware of any way to positively stimulate the plant to produce more cycles, but typically you can expect about 3-6 cycles a year in a mature plant. Disappointingly most flowers never turn into fruits, either due to difficulty in pollination or the plant's burden to produce a large quantity of fruit. You will notice that many of these plants have ten or more flower clusters on one branch so there is at least a lot of chances for fruits. When pollination occurs the flower will lose all of its petals and then either shrivel up or develop a green fruit that will eventually mature and ripen red.

Propagation of the Dwarf Barbados Cherry:
There are many options available for the curious grower to get a start on growing their own M. punicifolia but the most common is propagation by cutting. Growing by seed may yield high genetic variability (if you can get the seeds to germinate), this may produce undesirable offspring. Propagation by cutting will as always, produce an exact clone of the parent. This can be done by selecting a branch that has some hardwood as well as a few leaves (the hardwood is a darker color and of older age than the softwood which is newer and usually greenish). Fungicide and root hormone should be applied to the end which was cut for the highest chance of success. There are a variety of methods which may be used to stimulate root growth of the cutting, these would be placing it in a plant propagator (typically an aeroponic system) or most simply by placing the cutting about an inch or two in a well draining soil. It may take 1-2 months before you can see roots grow but don't get too hopeful as most cuttings won't survive so do more than one.

As a Bonsai:
The Dwarf Barbados Cherry does excellent in almost any kind of bonsai container. I have mine planted in a shallow rectangular container made of clay, but I have seen them do well in narrow but deep containers as well. This plant is perfect for bonsai culture as it grows new leaves and shoots readily yet maintains solid mature looking stems. The most attractive aspect of this plant as a bonsai is its numerous and persistent flowers in addition to its fruit.
Common pests and diseases for the Dwarf Barbados Cherry:
Personally I have found aphids to be the most devastating, they primarily attack the young flower buds and leaves. I take care of them by spraying a safe insecticidal soap twice a week until they are gone. I have heard that nematodes and pathogens are other common problems.

Friday, June 11, 2010

Bitter melon

Momordica charantia (aka bitter melon or bitter gourd) is a popular vegetable in many Asian countries and has an adamant place in Asian cuisine. Bitter melon's popularity doesn't stop at being a staple food crop, it's also used as a medicinal treatment for a wide array of illnesses, and it often consumed as a tea. It's a member of the Cucurbitaceae family along with cucumbers, and the resemblance is clear. The problem most people have with bitter melons is their bitterness, it is definitely an acquired taste. For culinary chefs the bitterness can be used as a compliment in their dishes, making the bitter melon very useful in cooking.

Growing this plant out of it's desired sub-tropical/tropical climate is very easy, but only as an annual. When growing bitter melon think of it as if you were growing a cucumber, start after the last frost of winter and expect them to grow until it gets cold again in fall. It prefers high humidity but they can still be grown in low humidity. You will find that this plant is a fast grower, but is even faster at blooming. I have noticed flowers on bittermelon vines that are only 6 inches long! As far as aesthetics go, it's not a terribly pretty plant and it has a very bitter smell. Just touching the leaves of this plant will make your hands smell with a spicy bitterness.
The varieties of bitter melons:
There are many different types of bitter melons with different textures, tastes, and sizes. The Indian bitter melon (below) is generally smaller and very bumpy. Chinese bitter melons (Top of page) are long and smooth and are a lighter shade of green. There are bitter melon hybrids that are white and some that are extremely long, some even have different leaf structures.

Seeding Bitter melon:
Collect hard seeds from the bitter melon, the soft white seeds aren't viable. You will notice red flesh surrounding each seed, if the flesh is white that means the seed probably isn't viable. Take the seed out of the pocket of flesh before planting. Expect about 15-30 seeds per bittermelon depending on their size and variety. You can either let them dry out or plant them immediately. Plant them about ¼ inch in a well draining soil and water daily. Germination period is around 7-14 days and time until harvest can be sooner than 60 days!

Growing conditions for Bitter melon:
I have noticed that these vines are mildly drought tolerant and do well even in excessively hot temperatures. Frost is deadly to these plants thus making it an annual, although in tropical locations it can survive as a perennial. Bitter melon vines can tolerate slightly acidic and slightly alkaline soils making them fairly versatile. A trellis should be provided if you want to keep this plant from spreading and taking over other plants. This way the bitter melon vine can attach its tendrils to the trellis as opposed to neighboring plants. Give this plant a lot of space, it grows fast and is ready to conquer a greenhouse or garden.

Pollination and harvest of bitter melons:
The bitter melon plant has both female and male flowers which means that a pollinator must carry the pollen from the male flower to the female to complete fertilization. The most common pollinators are bees and other flying insects, although if you don't have any natural pollinators or are growing in a greenhouse it is easiest to hand pollinate them. You can do this by using a small paintbrush and collecting pollen from a male flower and applying it to the female flowers. Typically the vines have far more male flowers than female flowers which means that most flowers will not turn into fruits. You can tell the difference between male and female flowers by the flower stem. That of the male will be long and thin while the female's flower stem will have a small unfertilized bitter melon attached to it. A pollinated female flower can be seen in the picture below.

How to cook bitter melon:
There are a wide variety of techniques when cooking bitter melon but most common are using them in stirfries and soups. Many people like to fry or pickle the bitter melons to add flavor and reduce bitterness. If used in a stir fry or soup you should cut the bitter melon in slices or in sections, but make sure no mature seeds are included. If you are using immature bitter melons you will notice that the seeds are small and soft making them edible. Bitter melons are commonly deep fried and often breaded too, making a nice snack food. The bitter melon itself is crispy and very watery with a spongy flesh on the inside with the seeds.

Bitter melon products are widely available and quite popular in many countries. You can find bitter melon as a flavoring in candies, bitter melon tea which claims to carry medicinal benefits, as well as bitter melon soda!

This is a box of Gohyah tea that is made with the bittermelon/bittergourd. Gohyah tea is dried slices or pieces of the bitter melon and it should be brewed just like any other herbal tea. The Vietnamese name for Gohyah tea is "Tra Kho Qua" while the Chinese name is "KuDing".

Saturday, May 15, 2010

Growing Zones

Knowing your growing zone helps you figure out what you can and can't grow in your climate. Traditional North American growing zones, or hardiness zones, are labeled 1-11 and include an (a) and (b) zone for each number. On the scale, 1 represents the coldest of zones while 11 represents the warmest. Each zone number corresponds to the average annual minimum temperatures of that zone, starting at zone 1 (-50F) and going up by 10F increments all the way to zone 11 (40F). The letters (a and b) represent 5F increments. For example zone 8a has a average annual minimum temperature of 10F-15F while zone 8b is 15F-20F. Typically for North America, the further north you go the lower the growing zone (colder) and the closer to the equator that you get, the higher the growing zone(warmer). There are a lot of factors that influence the minimum winter temperatures but most important are the distance to the equator, altitude, and distance from coastal regions.

This is the National Arboretum's USDA plant hardiness map of North America. For those in the United States hardiness zones can be found at Those living in other countries should check their government websites or their national botanical garden's website to find local hardiness zones. Many countries create their scale differently than the USDA scale. Some simply add more zones to the traditional USDA scale that go up to 13+ while others create a whole new scale. An example of this is Australia's hardiness zone map that can be found at

A good understanding of growing zones is crucial for growing any plants outdoors, and especially tropical plants. If you want your plants to survive winter it is important to know their hardiness and your growing zone. Most commercially grown plants come with the hardiness printed on the label so you can know if the plant will survive winter or not before you buy it. Its possible to grow plants that wouldn't normally survive your zone by either covering them during winter months, or putting them in a greenhouse. If you know of any hard freezes it would be wise to cover any cold intolerant plants with some sheets during the night. This keeps the plant a little bit warmer. Citrus trees are popular here in Arizona and they grow quite well but in many places people must still cover them for freezes to keep them from dying.

Some perennials and trees need chilly winters to survive and continue to grow the next year. The chill period first occurs during Fall, in which the deciduous trees lose their leaves. During winter months with chilling temperatures (~40F and below) plants such as bulbs and some fruit trees will become dormant. These "Stone fruit" trees (Almonds, Peaches, Nectarines, Plums, Apricots, and Cherries), some "Pome fruit" trees (Apples and Pears), and many berries (Blueberries, Blackberries, Raspberries) need a specific amount of chill time, depending on the variety and cultivar. This will range anywhere from a few hundred hours to two thousand hours. Areas like Hawaii and Florida in addition to tropical locations worldwide aren't able to grow such trees because they can't provide adequate chill time (if any at all).

Minimum temperatures have little variance in most tropical climates. Instead of having warm and cold seasons they typically have a dry and wet season. The dry season is marked by time period of lower than average precipitation/humidity; The wet season is usually marked by monsoon rains and is often referred to as a rainy season. Due to annual weather cycles the wet and dry seasons are predictable, but occasionally tropical locations will also have a cool season. A cool season is simply a season with slightly lower temperatures.

Friday, April 23, 2010

How to: Grow Avocado from seed

The avocado (Persea americana) is one of the more popularly cultivated tropical plants. A common name for this fruit is the Alligator Pear, named in part to its rough skin and pear shape. Its native to the Americas and has a wide variety of culinary uses especially in dips and sandwiches. The trees do best outside (in tropical/sub-tropical climates) where they will grow tall and fruit abundantly. The best areas for the cultivation of avocados are zones 9-11+. If you can protect your avocado from frost then growing in a lower zone may be possible. The best places to grow Avocado in the United States are California, Florida, and the lower states. If you are buying a live avocado tree, be sure to check it's hardiness; be certain that you can provide a warm enough environment for it. For those of you living in colder climates you can still grow avocados inside your house or in a greenhouse, although in these situations it will be unlikely that you get any fruit. When young the plant looks like a typical house plant, similar to a money tree (Pachira aquatica).

Next time you are making guacamole think twice about throwing away the pits. Have some fun with them, try growing them in water. This method is easy, fun, and rewarding, if you have a little patience. You will need three toothpicks, a small cup, and an avocado pit. First place your seed(s) in a glass of hot water (120-130F) to kill any possible avocado root rot pathogens. Place your avocado pit pointy side up and gently push in the toothpicks equidistant from each other just less than an inch from the tip. Now make sure you can suspend your pit on the rim of the cup. Fill the cup with water and put it just about anywhere that won't get too cold. Change the water often (1-2 times a week) to keep the necessary oxygen levels so that the roots can breathe and to prevent stagnation. Time for germination is anywhere from 3-6 weeks (or more) so this is where a good patience is needed. I have noticed that the warmer it is the faster they germinate so try to maintain a temperature range of 60-85F. I have had a 100% germination rate with my avocado seeds so they seem to be one of the more viable kinds of seeds out there. To improve chances of germination further be sure to plant soon after eating the fruit.

If you are serious about growing an avocado tree, plant your sprouted pit in a moist and well draining soil. You can skip the toothpick method and just plant the seed directly in soil which works great too, just isn't as fun. They do the best in somewhat sandy soils but most generic potting soils work well too. Make sure the soil and container have adequate drainage, poor drainage is lethal for avocados. The soil's Ph should be around 6 but don't worry too much about the Ph. Growing store bought avocado seeds doesn't always produce a true to type plant. This means that if you eat and plant a Hass avocado seed the result could be a tree that produces no flowers/fruit or bears fruits with a poor flavor, unlike that of the fruit which the seed came from. If you are worried about this being the case, don't hesitate from growing those avocado pits anyways, you can still use them as rootstocks. This means that you cut off the entire plant at the stem/trunk and graft on a branch from a productive avocado. Being so, the grafted growth will contain the exact same DNA as the parent of the graft resulting in a clone of the parent tree.

Each avocado variety has it's pros and cons so do some research. Some can take the cold a little better while some produce bigger fruit or different colored fruits. Some of the most popular varieties of commercially grown avocados are Hass, Reed, and Bacon. For serious avocado growers, you can mix and match rootstocks and grafts. For instance some people pick out a variety of avocado that does great in their soil conditions or is especially disease resistant for the rootstock and then find a heavy producing plant to graft onto the rootstock. This results in a specialized avocado tree that suits the growers' soil conditions and climate while producing the kinds of fruits that they love.

These two avocados were grown using the toothpick method. Every day I would check on them to see if anything new happened, but every day they were still just avocado pits in water. Just as I was about to throw them away I noticed that a thick taproot was coming out of both seeds. Growth was still slow though, I blame the cold winter months. I started them just about 6 months ago and they are already over a foot tall! All of the avocado seeds I have planted since have come along a lot faster, or so it seems. These avocados are taller than the ones I grew outside, this is because they received less light next to a window compared to outside in direct sun, and naturally grew up towards the sun. For these taller avocados (and all young trees for that matter) you should gently shake or tap the stem. This acts as an artificial wind. With this movement the plant releases chemicals that signal for the plant to reinforce its stem.

Further tips for growing Avocado trees:
  • Be sure that the soil is very well draining, soggy soils are deadly.
  • Keep on the lookout for avocado diseases, these can strike at a moment's notice.
  • Protect from severe heat by planting in partial shade or under a larger tree.
  • Protect from cold temperatures (Keep in mind an Avocado's hardiness varies by variety).
  • It may take up to 10 years or more before an avocado will bear fruit, so be patient.
  • Fertilize younger plants (Over one year old) with a high phosphorous fertilizer, while mature fruiting/flowering avocados should be given a high nitrogen fertilizer.
  • Use fertilizer sparingly, avocados are sensitive to over fertilization.