help with citrus trees!

[cheruna]

Hi,i am struggling to find fertilizers and pest control for our lemon,orange and mandarin trees,we have about 50 and are trying to be organic.can anyone help? We have problems at the moment of yellow leaves and insect damage and would love to find something to use.Any advice would be great,thanks

[starloc]

Organic fertilisers never work that well with citrus, due to the high level of nutrients they want, there are other problems with organic though, the main problem is that the roots are very sensitive to lack of oxygen, organic fertilisers tend to break down with bacteria causing a lack of oxygen in the compost, there are some that can be used but you are usualy beter not bothering with them, things like ox blood give a rapid nitrogen fix, but not as good as other fertilisers.

The main problem with having so many is that most do not need watering or feeding at the same times , the more you get the worse it gets, you need to be very carefull not to over water them as root damage due to oer watering can look like a nutrient deficiency.

What are you feeding them now, what are they growing in, have you got any pictures of the leaves?

Citrus are very very heavy feeders, and they need a lot of micronutrients in the mix, a lot of plants can do without the micronutrients but citrus can not, they are also very sensitive to the pH of the compost, if its slightly out the microntrients will not be absorbed, giving the impresion that there is a lack of nutrients, even though there is not.

I use a variety of citrus fertilisers, usualy i buy them on ebay , chempak and global oranage groves do one , both are very similar ,vitax do one, another is maxicrop seeweed based citrus fertiliser, there is also one i got from the citrus center

The chempak, vitax and the global orange groves do 2 types summer and winter feed you are suposed to use different ones summer and winter , the citrus center one is an all year round fertiliser, the same as the maxicrop one

I had best results with the chempak and global orange groves ones, followed by maxicrop citrus , the others didnt make the plants so happy, maybe just my plants but i dont think so.

If the leaves are yellow , mix up a dilute fertiliser and spray the leaves to give a rapid fix of feed , once a week

Depending on where is yellow on the leaves its a different defficiency, so once using a ballanced complete feed, you can spray the plant with an increased level of one of the nutrients, good ones to add are epsom salts for magnesium , or potassium nitrate (saltpeter) for potasium and nitrogen

the only one i tend to spray is the magnesium added to each spraying of normal citrus fertiliser
potassium nitrate is used when the plant is about to flower to get a higher fruit set

Theres an itallian book on citrus that covers some organic stuff to add like the ox blood and baked lupin seeds etc, but the problem is that they take effect very slowly compared to normal fertilisers

Organic pesticides, the best one is neem oil, or horticultural oil, horticultural oil suffocates pests and works ok, but neem is a natural pesticide and prevents them eating and scares them away as well, another is limonene ( distilled orange oil) it can be used in about 0.5 to 1 percent to water and it kills most insects on contact

There is a good powerfull pesticide, classed as organic....from usa called dipel , it can be sprayed on food and eaten the next day, it is used mainly for caterpillers and moth caterpillers that can cause major problems with citrus

If you have photos of the yellowing on the leaves it will be easy to check what the nutrient defficiency is.

[Flobalob]

Not a lot I can add to the imformative reply above, other than to ask for more information from you cheruna. The plants.. where are they growing ? What medium are they growing in ? age of trees, potted or in the ground ?

[cheruna]

Hi,thank-you so much for the advice,this is my first internet forum!I have been working my way through all the help you've given.Our trees are in spain all in the ground ranging from about 10-50 years old.we have orange,mandarin and lemons as our citrus.i can't upload pics at the moment.The idea of overwatering showing similar signs as deficiency is interesting as we've had an unusually wet winter this year and have stopped using our asequia(irrigation) water but can't stop the rain!i have decided to fertilize normally after your advice and bought sacks locally of complete citrus feed and am not trying to be organic for the citrus,it makes sense.The trees aren't in too bad shape,i wanted to treat them before they got any worse.Thanks again