Saturday, July 19, 2014

How to: Grow, Eat and Cook Jackfruit

Jackfruit trees yield the largest fruits of all fruit trees, with some weighing well over 50 lbs. This truly massive tree belongs to the mulberry family (Moraceae) and is known taxinomically as Artocarpus heterophyllus. It is closely related to but not to be confused with the breadfruit (Artocarpus altilis) which similar to jackfruit has a very sticky latex that exudes from severed leaves, stems and fruits.

Unfortunately, jackfruit tree cultivation is pretty much limited to the tropics as the young trees are sensitive to freezing temperatures. Aside from cultivation in Hawaii or certain regions of Florida, yielding fruit from one of these trees outside of an enormous greenhouse would be nearly impossible. Regardless, jackfruit trees may be grown to a limited size within a normal greenhouse or even in some cases indoors given adequate light. To grow a jackfruit you must obtain some seeds, and search no further than a fresh jackfruit.

To eat a jackfruit, first you must be sure that it is ripe. Jackfruits are typically sold immature, and unripe, these will be green and firm. As the fruit ripens dark patches and yellow color emerge, along with a very distinct and strong fruity smell. Additionally the skin of the fruit should give in slightly to pressure, indicating that the fruit is ready to be cut. To accelerate the ripening process, jackfruit may be placed outside in warm sunlight for a few hours or more. To slow the ripening process, jackfruit may be stored in the refrigerator.

Before cutting into a jackfruit, be aware of the powerful latex that resides within the fruit. If this latex gets on skin, soap and water will prove ineffective to clean it off. Instead, keep some cooking oil handy as the latex is easily removed with oils. Furthermore latex or nitrile gloves should be used to protect ones hands against the sticky latex. A long knife should be used to cut the fruit down the middle, be sure to apply a generous amount of oil on the knife before cutting the fruit to prevent the latex from adhering to the blade.

Pictured above is a ripe jackfruit with some slight yellow tinges and brown and black spots visible. Compare this to the unripe jackfruits pictured at the top of the page.

Cut the jackfruit longways with a large knife to expose the midrib and surrounding fruits. 

Carefully use a smaller knife to cut out the midrib from the rest of the fruit, as shown above.

Now it is possible to easily remove the yellow fruit pods from the stringy white filaments.

Finally, the seeds should be removed from the fruit pods so that the fruit may be eaten, cooked or blended in smoothies. The yellow flesh of a ripe jackfruit will taste like some kind of combination of banana, mango and pineapple. Don't discard the seeds as they may also be cooked and eaten, or planted to become new jackfruit trees.

Preparing and storing jackfruit flesh:
The yellow fruit pods of a jackfruit should be stored in airtight bags or containers for only a couple of days in the refrigerator. Since it's quite difficult to eat an entire jackfruit in a timely manner, I prefer to store the bulk of my jackfruit flesh in the freezer for long-term storage and for use in smoothies.

How to grow jackfruit seeds:
The seeds from jackfruit are large and full of energy for the developing seedling. This means that whatever method you choose to grow your jackfruit you will inevitably end up with a large and healthy seedling. One of the most important factors is planting fresh seeds, as older seeds become more dry their chances of germination dramatically decrease. To ensure success, simply place a jackfruit seed about 1 inch into well draining potting soil. The seeds may even be placed in a cup of water placed on a window sill, and eventually small roots and a stem will emerge indicating that it is time to transfer the germinated seed into soil. The seeds should germinate in about a month, but this will vary depending on climate and the freshness of the seeds.

Upon germination the young jackfruit seedling will grow rather quickly. The first few leaves will appear and enlarge in about a week. Within a few months the stem will thicken and more leaves will appear. Avoid fertilizing jackfruit seedlings for the first year or two and be sure that the soil is draining well as waterlogged soil is lethal.

How to cook boiled jackfruit seeds:
I like boiled jackfruit seeds, although they are also good roasted and in stir-fry. To boil jackfruit seeds bring a pot of water to boil (4 cups water per 100 seeds should do) and add a teaspoon of salt. Throw in the jackfruit seeds and let them boil for about 10 minutes and turn off the heat, letting the seeds steep in the hot water for about 5-10 minutes longer. The result is a starchy, soft textured seed with a mild flavor.

A cooked jackfruit seed should be peeled of the outer casing before eating.

Believe it or not, jackfruit trees are used for much more than their delicious and nutritious fruit and seeds. The latex is often used as a glue, while the wood is highly coveted for building furniture and houses. In many regions of the world this is a sort of miracle tree that provides shade, fruit, latex and wood.

Thursday, May 29, 2014

How to: Propagate Bananas

I recently set up a poll to gauge my readers' interest in the next propagation guide, but unfortunately there was a problem and it got reset. Last time I checked though it was neck-and-neck across the board so I'll just pick this time. If you have a particular interest in a tropical plant that I haven't covered please e-mail me and I'll see what I can do.

My curiosity in bananas has evolved throughout my life. It all started as a child when I wondered where bananas come from, since I had never seen a banana tree before. As I grew I discovered that banana trees aren't really trees in the traditional sense of the word, but instead very large 'herbs'. And now I know that bananas are much more than the ubiquitous yellow fruit found in grocery stores around the world. Bananas come from the diverse and intriguing genus Musa which comprises several dozen accepted species in addition to many hybrids. The single most successful banana hybrid is the Cavendish banana which has a fascinating and unfortunate history. The Cavendish banana is essentially every common banana found in the grocery stores (except maybe specialty grocers), it is the curved yellow fruit that everyone is all too familiar with. What may be less known is that the Cavendish bananas are sterile due to a genomic condition called triploidy, meaning that they contain a whole genome plus a partial set of a genome from the parent species Musa acuminata. One might ask, how are there so many bananas and how are they grown if none of them have seeds? This is achieved on a commercial scale using tissue propagation, which is essentially a process of cloning. However, there are many delicious seeded bananas that the average horticulturalist may grow quite easily. Thus the subject of this article arises: How to propagate bananas.

Banana trees are extremely fast growing, they are capable of going from seed to fruit in only a few years. These plants are most often tropical, desiring warm and humid climates, with a few exceptions. They grow best in full sun and in fertile and moist soil. Banana trees grow tall, with some reaching well over 20 feet tall. However, not all banana trees are created equal, they vary in size and shape and while some have green and yellow fruit, others have red or even pink fruit.

There's a very good reason that bananas aren't grown in most of the United States, and it's the freezing winter temperatures. Even a slight freeze (or general cold) is enough to kill a Cavendish banana tree, however there are ways to work around this. I have been able to grow dwarf banana trees in my greenhouse with few problems, they even go to fruit rather quickly. Supposing one is growing a dwarf banana variety, it is possible to cultivate it in a pot, leave it outside in the sun during summer and bring it inside for the winter. This will sap its growth and you may not get much of a harvest, but it's certainly worth the novelty factor. Furthermore, there are some banana species that can be grown in cold and occasional freezing temperatures, with the best example being the Japanese Fiber Banana, Musa basjoo, which although is inedible, can make for a great landscape ornamental.

What's the big deal? Bananas are inexpensive anyways - Right, well I have developed a keen interest in fruit diversity, and I'm happy to say that bananas are quite diverse. This is largely due to the compatibility of closely related Musa genomes, which in some cases allows different species to cross and form some very unique hybrids. There are countless banana species and hybrids with varying ploidy levels (i.e. varying genome size and composition) which yield fruits of varying sizes, shapes, colors and tastes. In fact, just as there's a wide selection of apple fruits, so too is there of bananas, so why can't we buy them at grocery stores? This is for two reasons, one being lack of customer awareness, and the second being that the Cavendish banana currently seems to be the easiest to grow on a commercial level. So if you're curious about the other flavors that exist in bananas, you can always purchase some exotic cultivar banana seeds from the internet and grow them yourself.

Growing bananas by seed:
This is essentially the only option for most first-time banana growers, and it's pretty straightforward and easy. The first step is to find some banana seeds, but don't settle on just any banana seeds, find a cultivar or variety that interests you and suits your location. Two easy to find banana seed types that are perfect for beginners are those of the dwarf Cavendish banana and pink banana. These are readily available on the internet and are relatively fuss-free for greenhouse cultivation.

Once you have some banana seeds, be aware that germination may take a long time, at least a month but in some cases much longer, up to a year. The more fresh the seeds, the faster and more efficient germination will be. My method of choice for most tropical seeds is the moist paper towel or soil in a plastic bag. While this will work for banana seeds, to increase germination even further I will do a modified protocol.

On the left are seeds from a dwarf Cavendish variety (Musa acuminata) and on the right are seeds from a pink banana (Musa velutina).

Banana seeds may be scarified, this is the process of breaking the seed coat so as to increase germination. To do this simply take a knife and create a small notch or scratch on the hard outer seed coat, but be careful not to crack the seeds, as old seeds may be quite fragile.

Now place the seeds in warm water for 24-48 hours to allow the seeds to imbibe water. Ideally the water should be warm (70°-85°F), so if your house is cold, simply place the water soaking seeds in the warmest place or utilize a seed germinating heat mat. 

Finally comes the long haul. For this I will use a tupperware container with some moist potting soil and I will gently sow the seeds about 1/8-1/4 of an inch down. Then I place the container on a warm and light window sill and begin the wait. Mist the soil as it becomes dry, but don't over water as the soil should never be wet. Be careful to not allow fungus to grow in the container, you may use a gardening fungicide if this becomes a problem. Alternatively, you may place the seeds in a bag containing moist soil or a moist paper towel and achieve similar results.

After the banana seeds germinate and form roots and a visible stem, they may be transplanted to small pots. They will inevitably germinate at different times so be prepared to transplant them on an as needed basis. As the banana seedlings begin to grow you will need to scale up the size of pot that they are growing in, or eventually plant them directly in the ground.

Growing bananas by tissue culture:
Commercially, bananas are propagated via tissue culture, resulting in clones of a single plant. Tissue culture is a powerful method of propagation, one that can yield nearly infinite replicates of a tried and true plant. In the case of bananas, a cluster of stem cells called the meristem is cut out of a banana tree and subsequently divided into many pieces. Each piece of the meristem can be grown in petri dishes containing nutrients and growth hormones. This stimulates the meristem to grow appropriate tissues such as roots and leaves. These clones may eventually be transferred to soil and grown into banana trees for the commercial industry. Therefore, each banana you buy from the store is likely genetically identical to the last bananas you purchased. Tissue culture is a tricky process, something that is seldom done outside of a laboratory setting as it requires sterile conditions and skilled hands.

Growing bananas by 'pups':
'Pups' are the small plantlets that emerge from the base of a banana tree. Typically these are removed as the parent banana tree is growing so as to focus the plant's energy on growth and banana production. However once the banana harvest has developed, the pups may be left to grow. Upon harvest, it is possible to have many small banana plantlets at the base of the parent plant (which dies after harvest). Overtime these plantlets will grow into the next set of banana trees in a cycle that can perpetuate harvest after harvest.

A dwarf Cavendish banana flower and immature bananas.
A small harvest from the dwarf Cavendish banana tree grown in my greenhouse.

The bananas were small but delicious, with the typical Cavendish flavor however the texture was a bit chewy.

Banana cultivars from left to right: Cavendish, plantain, Saba, Burro, Chuoi su, Manzano.

There is an array of bananas available at specialty grocers and Asian markets. One of my favorites is the baby banana type called Manzano, which is Spanish for apple tree. This small, sweet banana holds true to its name and tastes like a combination of apple and banana, they are very sweet with a smooth texture. 

Saturday, November 30, 2013

South African Spiny Cucumber

The family Cucurbitaceae is a diverse family with many well known agricultural crops including gourds, squash and cucumbers. The genus Cucumis is probably known most for the delicious cucumber fruits of Cucumis sativa. However this genus has many other very interesting species one of which, Cucumis metuliferus, yields spiny edible fruits. The much less known Cucumis zeyheri, which I will be focusing on in this article, is a native to Africa. It is known as the South African Spiny Cucumber and can be found growing wild in some areas of South Africa. The plant vines profusely and grows well on the ground or climbing on fences or trellises. Although bitter the fruits can be eaten raw or pickled, but they may be better purposed as medicine. Because of their bitterness, the fruits may be used to induce vomiting, and they may contain compounds with medicinal properties. 

I've tried my hand at eating these fruits, and I'm rather dissatisfied. The fruits are indeed very bitter, plus they have a thick wall and many seeds. Waiting until the fruits are yellowed and fully ripened may reduce the bitterness. I find that growing the plants for ornamental value is more rewarding, and because they are native to a dry warm climate they grow very well in my backyard. Propagation by seed is very easy, and is identical to growing cucumbers or any melon by seed. Simply sow the seeds in spring about 1/4cm deep in soil and water periodically. It should be treated as an annual, growing quickly and setting fruit in a single season. I have found that this plant is relatively drought and pest tolerant, making it low maintenance. 

The purpose of making this article isn't to exhibit this plant's edibility, rather to showcase it as a potential candidate for crossing and breeding programs. In today's world water is very scarce and any drought tolerant plants should be examined as potential building blocks for the crops of the future. Additionally, its close relation to the agricultural cucumber makes this plant, and all others in the genus potential targets for crossing experiments. If this is your interest there is abundant literature and research done on this genus, and detailed information about previous crossing experiments and sexual boundaries exist.

Sunday, August 25, 2013

Batumi Botanical Gardens

Nearly 10 kilometers north of Batumi, Georgia is a massive 111 hectare botanical gardens called the Batumi Botanical Gardens. This is the most developed botanical gardens in Georgia and it deserves world recognition. The gardens have many historical buildings, some of which house the families of workers, and others house offices of botanists and directors. The gardens have a small herbarium that houses a few thousand specimens from around Batumi and others collected from the gardens. The Soviet Union provided much funding for the gardens in the past, and since the fall of the USSR, private investment has continued to fund development and maintenance of the park. The gardens are currently building many new greenhouses to replace the older outdated greenhouses.The grounds are quite expansive with many roads and trails. Everyone says that seeing the gardens in a single day is impossible, but you can at least see the areas that interest you.

Pictured above is the first map of the gardens. The left side shows the Lower Park in detail with numbers highlighting specific plants. On the right is a map of the whole garden, which comprises of 21 different "parks" or sections.

This thick foamy bark may not look so familiar but in fact you are looking at the Cork Oak (Quercus suber), the source of cork for wine bottles.

Above are some kiwi vines that I found engrossing a tree's lower branches.

A lush view from the Gardens looking down to the Black Sea.

A banana flower from a Musa basjoo plant. This is known as the Japanese Fiber Banana because it is commonly used as a source of banana textiles and cloth in Japan. Unfortunately the fruits aren't edible.

This is an example of the Bamboo forests at the garden. The type of bamboo is Phyllostachys edulis. This bamboo can grow a hundred feet tall and yields edible shoots. The thick and sturdy stems have many uses, and I assume that it's from these stems that vendors in Batumi make their souvenir bamboo creations.

This tree (Liriodendron tulipifera) fell during a strong storm and created a walkway between two paths in the gardens. The tree survived despite the shock and new shoots began to grow out of the fallen trunk. Now the tree has many trunks and is quite an interesting specimen, and it's still a functional bridge.

An unripe Japanese Persimmon (Diospyros kaki) from one of many such trees in the gardens.

Tuesday, July 9, 2013

Plants of Armenia

Recently I was in Armenia for a collection trip and I thought it would be a good opportunity to highlight the fruits of Armenia. Due to Armenia's geography and lack of a coast, there are no tropical regions, therefore they do not cultivate tropical plants outdoors. However, Armenia does have some sub-tropics type regions in which some nice and unusual fruits are cultivated. Many common and popular fruits in Armenia include pears, apples, figs, apricots, peaches, grapes, and pomegranates. It is thought that Armenia was the origin of cultivation of grapes leading to the production of the world's first wine! Therefore grapes have an important place in Armenia's history and are still cultivated in many areas across the country.

Across the country apricots are plentiful and it is Armenia's national fruit. It's not surprising that Armenian's are crazy about apricots; Armenians pride themselves with their quality apricots which are absolutely delicious. In addition to apricots, Armenians favor the pomegranate. In Armenia there is much myth and lore surrounding pomegranates, and they are used as a symbol of fertility. The Armenians are also known for making a sweet pomegranate wine.

This is just one example of the many fresh fruit stands that are abundant across the country. During the summer the most common fruits are apricots, apples, pears and figs.

Armenia is host to many wild populations of Rosaceae, and many in the genus Rosa. Rose hips are also cultivated in Armenia, and although these fruits are excellent in a variety of culinary uses, I think I like them best fresh off the bush! This species (Rosa hemisphaerica) is unusual in having bright orange hips, which are especially delicious.

Armenia's Institute of Botany and Botanical Gardens in Yerevan has suffered since the collapse of the Soviet Union, as has the whole country. The garden still seeks financial aid and investment from foreign resources, but it is not enough to repair some of it's crumbling infrastructure.
The greenhouse at Armenia's Botanical Gardens in Yerevan is still functional to a certain extent, although many windows are missing and the structure is in need of repair.

The greenhouse has many interesting specimens including members of the family Juglandaceae. These are a couple of walnut fruits from the genus Juglans.

Although the institutes main greenhouse is in poor shape, there are other greenhouses at the gardens. This greenhouse contains many tropical houseplants and fruit trees in addition to cacti and succulents.