The Tropical Fruit Forum

Brian, most citrus nurseries purchase their rootstock seed from large companies that maintain  groves of trees for the various types of rootstock seed that they market.  Following is the procedure that is commercially used by major companies that market Poncirus Trifoliate seed. You can adapt  from this.  The process of producing large volumes of rootstock seed includes harvesting the fruit at normal maturity, crushing the fruit in water, stirring the resulting mixture with pectinase enzymes at specified temperatures to separate the seed from the pulp, and washing out the seed.  The washed seed has its surface sterilized with 125-F water for 10 minutes, then dipped into a 1 percent solution of 8-hydroxyquinoline sulfate (8HQS), then left to air dry on screens in the shade, and packaged in plastic bags.  When storing, it is important to leave these storage bags open initially until the seed equilibrate with the refrigeration temperature.  If the bags were closed before refrigeration, the undissipated heat and humidity may generate condensation inside the bags which promotes fungal pathogens.  Fresh used citrus seed has the highest germination percentage, however seed can be stored at 40-F for as long as 6 months with little loss of viability.  Seed stored at room temperature looses viability quickly.    NOTE: 8-HQS is just a common bactericide,  if you can't locate it, there are a lot of bactericides that can be used. Be sure that the medium that you plant the seed in, and the seed tray used are completely sterile .  Nurseries that purchase the seed and grow them out add dolomitic limestone to the seedling medium to maintain a pH of 6 to 7, plus controlled slow release fertilizers with micronutrients.  The seed is planted 1/2 inch deep.   Humidity maintained between 80 and 90%, temperatures are kept at 85-F.  Germination is further enhanced by pealing away the testa (outer seed coat).  Germination is further enhanced if the seed trays can be heated from the bottom to maintain the 85-F temperature in the media. Following the above procedures seedlings 2 inches tall with three leaves can be achieved within 10 to 14 days after planting, though it can take as long as 40 days for all the seed to germinate. - Millet

Luak, papayas are easy to grow, and can produce fruit in the first season, surely in the second season  Never ever water a papaya with cold water, as they get root rot very easy.  Grown from seed there is a chance that your papaya can turn out to be a male tree, a female tree or a hermaphrodite tree.  Both the female or the hermaphrodite tree will give you fruit.  A male tree just produces pollen but does not fruit.  Keep your fingers crossed.  The T.R. Hovey Papaya is a dwarf papaya that produces regular fruit, and can be easily grown in a 5 gallon container.  T.R. Hovey Papayas can be purchased from Logees Greenhouse on line if your interested.. - Millet

The U.S. Department of Agriculture has adopted a rule that will reduce the size and grade requirements for grapefruit and oranges that are grown in the lower Rio Grande Valley of Texas. These rules are in response to market demand and maximize shipments of fresh fruit. The new rule changed the size requirement for grapefruit from 3-5/16 inches to 3 inches in diameter and oranges from 2-6/16 inches to 2-3/16 inches in diameter, lowering grade requirements for smaller fruit. Consumers are now showing a preference for smaller-sized fruit, and believe relaxing the requirements makes more fruit available to fill the market shortfall and provides smaller-sized fruit to meet consumer demand. Grapefruit that doesn't meet the size requirement goes to juice giving the grower less of a profit, returns are better for fresh fruit. In 2013 the Rio Grande Valley of Texas produced 5.3 million cartons of grapefruit and 1.7 million cartons of oranges. - Millet

All Harris County Citrus Trees Under Quarantine

(HOUSTON) — All citrus trees in Harris County are now under quarantine for a tree disease that has already devastated the Florida citrus crop.
Monte Nesbitt, a horticulturist with Texas A&M’s Extension Service, says it’s not dangerous to eat fruit from a tree infected with citrus greening, but it might not taste good. The fruit never matures beyond the green stage.
It’s called “citrus greening” — a bacteria that can kill a lemon, orange or grapefruit tree within two years.
Although the disease hasn’t been widely detected in Harris County, there is also no known cure for citrus greening, which prompted the quarantine.
“Which means we don’t want plant material to move out of that area that’s already infected,” Nesbitt said.
Nesbitt said they are also fighting the spread of citrus greening by using insecticide on the bug that carries it from tree to tree.
“It’s about the size of the tip of a toothpick; white or tan in color,” he said.
If you have any questions, Nesbitt says call your extension agent.
A typical tree infected with citrus greening will have leaves that turn a mottled yellow. - Millet

Commercial citrus types differ in cold hardiness.  Mandarin trees are most hardy  followed by (in order from most hardy to least hardy) Sour Orange, Sweet Orange, Grapefruit, Pummelo (Shaddock), Lisbon lemon, Eureka lemon, Tahitian lime, Mexican lime, and citron.  Trees of citron, lime, and lemon are least hardy because they tend to grow continuously and flower and fruit in cool weather.  On the other hand, grapefruit, sweet orange, mandarin, and kumquats are more frost hardy because their growth stops in cold weather. Also, a tree's tolerance to frost is not the same as the fruit's tolerance to frost.  For example, although satsuma mandarin trees are very cold hardy, their fruit are small and thin skinned, which makes them more susceptible to frost damage than grapefruit, which are large and have a firm rind. Another factor responsible for differences in frost tolerance is the maturity of the fruit.  Fruit that is closer to maturity at the time of a freeze can withstand more cold than immature fruit.  For example, although Valencia and navel trees are equally cold hardy, navel orange fruit  are generally more cold tolerant than Valencia fruit because navel fruit mature earlier and have a higher sugar content during the coldest months.  - Millet

Psylids,, the insect that spreads Greening Disease (HLB) has been found in mailed packages going through Fresno mail distribution centers, which further raised the risk of the insects ending up in California's South Valley and the many citrus growing areas around  the world the post office serves. - Millet

The Texas Department of Agriculture temporarily has banned the sale of citrus plants in Harris County Texas after citrus greening disease was identified in stock at a local retail nursery near Webster. Hidalgo and Cameron counties also are under the quarantine designed to slow the spread of the plant disease. Once a tree is infected with citrus greening, there is no cure. Over a million acres of citrus crops have been wiped out across the U.S.  Citrus plant sales are on temporary hold while the department works with retail and wholesale nurseries to determine the best way to control the spread of the disease. The disease was discovered in the United states in 2005 in Florida and first discovered in Texas in January 2012.  - Millet

Mark In Texas, I forgot to ask, did you have some carry over fruit remaining on the trees that have not yet flushed new growth? - Millet

A good "insecticide" for a grower is Horticultural Oil.  Horticulture Oil is a paraffin based liquid that kills mites, aphids, white fly,  and mealy bug, the big 4 that attack citrus.  Horticultural Oils are 100 percent safe for people, and  is even also OK for organic culture.  Works very well. - Millet

jmc, your plan sounds interesting, it would be nice if you would keep us up to date as you proceed with your solar system.  My passive solar drums does help allot in lowering my greenhouse heating cost, but as my greenhouse is in zone 5 and additionally at an elevation of 5440 feet above sea level (1,800 M) still requires additional heating during our cold winter months. The 100 drums actually have not cost me the loss of usable greenhouse space, because I use them as a bench with containerized plants on top of them.   The best to your plans. - Millet

Jeff all drums are black plastic 55-gallon drums tightly sealed. - Millet

I have diabetes, so can't drink orange juice, but can eat oranges, which I really like. Page mandarin, Xie  Shan satsuma and Cara Cara are my favorites.  Ponkan is also great. - Millet