The Tropical Fruit Forum

I red in an article that in Spain it is illegal to put a bee hive within 2 miles of a clementine citrus grove, because if the grove is pollinated by bees the fruit will  then contains seeds.

http://www.growingproduce.com/citrus/planting-citrus-under-protective-screen-goes-commercial/

Laaz really nice seeing you again.  Your the man when it comes to citrus forums.  How are your dogs?  Do you still have the Sunrise Lime that Citrus Joe sent you?

I go along with La Casa Verde on the cold hardiness of grapefruit.  It is the older very large think branched grapefruit trees that survive some freezes.  Otherwise - dead.

Adrino2 -1.9 C equals 29-F.  I doubt that a brief low temperature of -1.9-C would cause any damage except possibly to a new young seedling. .

Cold weather is on its way, and many people are concerned about their citrus trees. One of the most common questions I get from gardeners is, "How much cold can citrus trees tolerate?" Because there are a number of variables, it's difficult to pin point a "threshold" temperature at which it becomes necessary to protect your trees.

There are three basic factors in determining freeze susceptibility of citrus trees.
The type and age of the citrus: Satsumas are the most cold hardy of the commonly grown citrus species in Louisiana. Kumquats follow with just a slightly less amount of cold hardiness. The order from most cold hardy to least cold hardy are: satsuma, kumquat, orange, grapefruit, lemon and lime. A citrus tree increases in hardiness as it gets older. Older trees with larger, denser canopies deal with the cold better as they trap more heat than smaller trees or unhealthy trees with thin canopies.
How cold it gets: Threshold temperatures are approximately 20 degrees for satsumas and kumquats and about 25 degrees for all other citrus trees. Trees will be damaged or killed by temperatures in the teens.

The duration of the sub-freezing temperature: If the temperature is below freezing for 24 hours or more, you should expect damage. All ripe fruit should be harvested from trees prior to a significant freeze. Temperatures cold enough to damage the tree also will ruin the fruit. It takes temperatures in the mid- to low 20s for five to 10 hours to freeze the fruit. The most cold hardy parts of the tree are the mature wood of major branches and the trunk.


If a citrus tree is gradually exposed to cooler temperatures, a process called hardening occurs, and trees become more tolerant to freezes. Chilly but above-freezing nights (in the 30s and 40s) that occur during the fall and early winter make the trees better able to handle freezes.

Severe freezes taking place when only mild weather has occurred previously are more likely to cause significant damage. This has been a relatively warm fall so our citrus trees are not well hardened at this point. Still, the temperatures this weekend should not produce severe damage.

The best way to lessen cold damage to citrus is to maintain healthy trees. Cultural practices that tend to induce and maintain dormancy in winter should be used. These methods include avoiding late summer or fall fertilization or pruning. Vigorous trees may recover from cold injury. Weak trees that are showing disease, insect damage or nutritional deficiencies are the ones most severely damaged and are the slowest to recover after freezes. fore covering, the tree could be generously wrapped with small, outdoor incandescent Christmas lights to provide additional warmth and increase the level of protection. Incandescent Christmas lights will not damage the tree even if they come into contact with it.

The frame and cover could stay in place indefinitely, but will need to be vented. Air temperatures within should not be allowed to go above 85 to 90 degrees. Venting should be provided on sunny warm days to prevent overheating and to maintain a supply of fresh air.

For trees too large to cover, banking the lower trunks of trees with soil or using tree wraps of bubble wrap, foam rubber or Styrofoam will help prevent cold damage to the trunk. This must be done before the first killing freeze and can be left on through the winter. Trunks should be treated with a copper fungicide before wrapping to prevent disease. Or the coverings could be applied during freezes and removed during mild weather.

Although tree tops may still be lost during freezes, a tree can recover if its trunk and root system are intact. Banking or wraps should be removed in the spring.

If the weather has been dry for a week or more in advance of a cold front, water your citrus trees. Trees that are drought stressed may experience more cold damage. This should be done a day or two before the freeze is expected.

Do not prune in the late summer or fall. Late pruning stimulates new growth that may not mature before winter, making it more prone to cold damage. In addition, pruning reduces the size of the canopy going into the winter, and this also reduces cold tolerance.

If pruning is needed, it should be done in early spring. Cuts should be made at branch crotches leaving no stubs. Prune to maintain a full, dense canopy. Trees need good leaf canopies to cut wind speed through the canopy and reduce the rate of cooling.

Leaves radiate heat to each other. Outer leaves may be lost to a freeze, but complete loss of inner leaves is averted by a thick canopy.

Fertilizer should be applied to citrus trees in late January or early February. A general-purpose fertilizer or citrus fertilizer may be used following label directions. Spread the fertilizer around the edge of the branches in the area of the feeder roots. Late summer or fall applications of fertilizer should be avoided as they can reduce the cold hardiness.

Avoid using oil sprays to control insects during the fall and winter. Horticultural oil sprays may decrease cold tolerance.

We potentially have a lot of cold weather yet to come this winter. Cover smaller trees as needed to protect them, and protect the trunks of larger trees if practical.

Keep things in perspective. We generally do not see significant damage if temperatures stay in the mid- to upper 20s and only stay below freezing for a few hours

http://www.nola.com/homegarden/index.ssf/2016/12/how_to_protect_citrus_trees_fr.html

Tom you had a big harvest this year. Congratulations.  Meyer lemons certainly are vigorous trees. With that many lemons, you must have juiced and frozen the juice for later use.  My new in-ground Marsh grapefruit fruited for the first time this past season with three nice sized fruit.  They are just now starting to turn color.  I will not pick them until March.  The Ponkan has too many fruit to count.  I ate the first one just this morning.  They are not quite ready yet, perhaps another couple weeks. This is the second year that the Saint Dominic Sour orange has fruited, perhaps 40 fruit.  Probably enough to make marmalade.  This is also the first time my in ground Valentine pummelo fruited with 3 fruit, all in a single bunch.  Next year  should produce a much better crop. My oldest tree is an in ground Cara Cara. It produced a bumper crop with fruit well distributed throughout the tree.  Its a bit early to pick them, perhaps in a couple more weeks.  I planted a Dekopon in the ground three years a go. It produced two fruit last year, and 15 this year.  It will be a couple months before I pick them.  From what I read March will be about the right time to try eating one. .  The Dekopon certainly produces very large sized fruit.    I did pick and eat some green Finger limes this morning.  I like the crunchiness and acidic taste they provide.  Would be a good fruit with fish.  Logees has red Finger lime for sale, I'm thinking of purchasing one to keep the green Finger lime company.

Mike, I've spend two hours studying your adventure,---  amazing.  Thanks for sharing your trip with us .  On the section about the  finger lime, I red that the native habitat for the tree is as an under story tree growing in the shade.   My Red Finger lime (container) has always been in direct sun the full day.  I've always had the thought that the tree seemed to be stressed. Perhaps dappled light would be better. Anyway, over the years, reading here, and on the Citrus Growers of your adventures far and wide in search of citrus varieties of all sorts its given us  a view of areas unavailable to us.   One of the very best sites on the Internet for anyone interested in citrus is Mike's home site  http://www.homecitrusgrowers.co.uk/  well worth visiting. I highly recommend it.

Flying Dragon Nursery Jacksonville, FL  -  Sold Under the name Red Navel Orange
http://www.flyingdragoncitrusnursery.com/fruit-tree-types/

Is your heater the type that does not put out ethylene gas as it burns?

http://www.growingproduce.com/citrus/varieties-rootstocks/experimental-florida-mandarins-measure-up/2/

http://www.npr.org/sections/thesalt/2016/12/04/503183540/after-a-sour-decade-florida-citrus-may-be-near-a-comeback