วันศุกร์ที่ 3 ตุลาคม พ.ศ. 2551

How to Grow Durians # 1

How to Grow Durians
(Hawaii growers click here)



Latitude: The durian tree is ultra-tropical, a native of Southeast Asian equatorial rainforests, and needs much tropical warmth, abundant moisture, and sunshine to thrive (except for the young trees’ first year, when semi-shade is preferred — simulating rainforest conditions). Most commercial durian cultivation in Southeast Asia is located within 15 degrees latitude of the equator, and some literature has suggested that 18 degrees north or south is the limit at which durians can thrive. However, growers in the Hawaiian Islands have demonstrated that durian cultivation is quite possible as far north as the island of Kaua‘i at 22 degrees north
(1 degree latitude equals about 70 miles or 112 km, at these latitudes). And in Thailand, one of the established commercial durian-growing areas is in the northern province of Uttardit, not far from Chiang Mai at 18 degrees north; the southernmost point of land in Hawai`i is only about 70 miles [115 km] further north in latitude than this. Successful durian cultivation is very unlikely outside the tropics.

Altitude: In Sri Lanka, the upper elevation limit for growing durians is said to be 600 m [2000 feet]; in the Philippines, 700 m [2300 feet], in Malaysia, 800 m [2600 feet]. These are the upper limits at which it’s possible to grow durians at all, though, not the optimum; on Penang island in Malaysia, few productive durian farms are above 300 m [700 feet]. These places are also all relatively close to the equator, which suggests that the altitude limit for successful durian growing in areas further away from the equator like Hawai‘i may be considerably less, perhaps 300 m [1000 feet] at the most, with best growth and production at the lower elevations.
It will take some experimentation by growers at marginal altitudes in more northern or southern tropical areas (such as Hawai‘i) to determine just what is the upper limit for growing durians there. The Hawaiian islands in particular have so many microclimates depending on elevation, wind patterns, terrain, and existing vegetation that it may be difficult to give any set rules for this. Some higher-elevation microclimates as on the south slopes of gulches, may be suitable though the surrounding area is not.


Regarding altitude and climate, coconuts may be a fairly good indicator as to the likelihood of success with growing durians: if coconut palms can grow and bear well in your micro-climate… except for seaside areas [durians are not salt-tolerant], durians may be possible too.
Temperature: For an ultratropical, durian is surprisingly tolerant of relatively low mean temperatures. There are places on the island of Java between 400-600 m [1300-2000 feet] altitude where durian is successfully grown that have a mean yearly normal temperature of just 23º C. (73º F.)

Some research has indicated that growth is limited below a mean monthly temperature of 22º C. [71º F.]. The trees may survive occasional dips in temperature as low as 10º C. [50º F.], but may drop their leaves. On the other end of the spectrum, durian trees in India sometimes successfully tolerate high temperatures up to 46º C. [114º F.].

Water: Durian trees need abundant rainfall, or equivalent irrigation. In most areas of Asia where durians are grown, mean annual rainfall is greater than 2000 mm [75 inches]. Historically, though, the better production sites have developed in areas with annual mean rainfall totals of 3000 mm [125 inches] or more, well distributed throughout the year. There is no doubt, though, that drier zones can produce good crops with appropriate irrigation. In India, durian trees are often planted along the banks of streams, where the roots can reach water. They do not do well very close to the ocean, having almost no tolerance for salinity in the soil.

Established durian trees cannot withstand more than 3 months drought without suffering irreversible damage. However, in places fairly close to the equator (such as Malaysia), three to four weeks of dry weather and relatively dry roots are needed to provoke the tree to flowering. Without a sufficient dry period, there will be no fruit that season. Farther from the equator, on the edges of the tropics (as in Hawai`i) where weather patterns start to somewhat resemble the four seasons of the temperate regions, this dry period is not necessarily required, and flowering is influenced more by day length and seasonal temperature.

Soil: "Rich soil conditions will make the tree grow well and fast. Sometimes four to five-year old trees can start to flower. The secret is in the soil. Organic fertilizer will improve the soil by balancing the pH level. This will produce quantity and quality durians."—Bao Sheng Durian Farm website, Malaysia

Favorable terrain for good durian cultivation ranges from flat to steep. In Chanthaburi province, Thailand, which leads the world in quantity of annual durian production, many durian plantations are on relatively flat land. In contrast, on the island of Penang, which has the reputation for growing the finest connoisseur durians in Malaysia, all the durian farms are on tall hillsides and valleysides, many of them fairly steep. The root system of a durian tree is very sensitive to standing water, and good drainage is essential, which is well taken care of by such sloping situations.

Durian trees grow best in a rich, deep, well-drained sandy clay or clay loam (deep alluvial or loamy soil), high in organic matter, pH range of 6 - 7. Heavy clay soils are not supportive of good durian tree growth and health, as they do not drain well. Seedlings make more vigorous growth when potted into media that is light and sandy rather than high in clay content.

In Thailand it is commonly recommended that growers avoid using organic animal manure, as the most troublesome disease of durian trees there, the fungal Phythophera palmivora, is encouraged by the moist fertile conditions at ground level around the trunk created by manure and mulch. It is not clear that such advice holds true for conditions elsewhere, however, and when using good organic tree planting practices. Traditional organic fertilizers are used with good results in Malaysia and elsewhere.

In many places in Southeast Asia, semi-wild durian trees thrive and bear perfectly well on their own with relatively little care. Maxing out the health of durian trees of choice varieties with modern organic methods and soil amendments such as compost and rock dust is likely to produce bumper crops of humongous spiky fruits of unimaginable and staggering deliciousness! Amen. :-)

READ NEXT PAGE DURIAN PAGE #2 : >>>CLICK<<<
READ NEXT PAGE DURIAN PAGE #3 : >>>CLICK<<<
READ NEXT PAGE DURIAN PAGE #4 : >>>CLICK<<<

0 ความคิดเห็น:

แสดงความคิดเห็น

สมัครสมาชิก ส่งความคิดเห็น [Atom]

<< หน้าแรก