Citrus seedlings, some odd observations.

[Heinrich]

Since winter 2013/14, I raise citrus seedlings of store bought citrus fruits. Here, I want to report about some odd observations, which often didnīt give plants. Usually, I put the seeds in a sand and peat filled pot, bag the pot and put it on a warm place with some light. Raising citrus seedlings plants is an easy task, but sometimes, unexpected facts result in failure.
Germinating seeds are very sensitive to environmental stress and pathogens. If the first and only growing point, the meristem of the shoot between the cotyledons, becomes hurt, there is no other meristem to continue the development.

2 cotyledons of a Meiwa Kumquat seed. Two and a half years old. It gets regularly watered, still alive, but unable to grow. Chances are small, it will ever become a tree.


This winter, I bought some exceptionally large Nagami Kumquats. So, I decided to raise the seeds. Six, out of ten seedlings, showed white leaves with only traces of chlorophyll. These plants are unable to photosynthesize and will die off, sooner or later. I wonder, if these Nagami Kumquats fruits have been treated in some way?


For unknown reason, some seedlings have a big problem to get the first leaves out of the seed coat. It can take a long time for the leaves to emerge and sometimes such seedlings fall prey to rot.
A Nagami kumquat seedling finally came out of the seed coat.


A 3 years old tangor, raised from a seed of Afourer/ Nadarcott. This tree shows a nice curved bump on the base of the stem, telling about its early days, struggling with seed coat.

[brian]

I believe someone (Millet?) has posted before about carefully peeling the outer seed coat off to help with this particular problem.  Never tried it myself as I've only intentionally grown trifoliate orange seedlings.  The majority of my seedlings don't live more than a few months, but enough do that it meets my rootstock needs.   

I've accidently sprouted many kumquat seedlings by spitting the seeds back into the container.  They look really nice, but I've never let them grow up.

[Millet]

Heinrich, thanks for the pictures.  I really enjoyed seeing natures struggle to survive.   

[Heinrich]

Brian, did you see occasionally white kumquat seedlings, too.

[brian]

No, mine are always glossy dark green.  I feel guilty pulling them as they look so nice.

[Heinrich]

Brian and Millet, thank you for your advice, carefully peeling the outer seed coat. I will do it, when I sow some citrus seeds again.

[Lory]

All your seedlings look HEAVILY overwatered, you even have moss growing on the soil.
Resuce the water and geve more light, they will surely improve.
As for my experience lemon, kalamansi, orange seedlings grow like weeds

[Heinrich]

Lorenzo, sure most citrus seedlings grow like weeds in the tropics. However, it is not so easy in my climate zone. When I sow citrus, it is winter and it is cold. Inside the heated houses, light and humidity levels are low. Therefore, I bag the pots and put them on a heating map. Under such conditions mosses start to grow, often before the seeds germinate. Later, when the seedlings are uncovered and the conditions are much drier, the established mosses stay and give a wrong impression about the watering regime. These seedling are not overwatered. I could improve my results, if I give additionally artificial light, also. I didnīt use grow light technology yet, but may utilize it in the future.

[Ilya11]

To get rid of moss you can use iron sulfate, it is available in any garden center for spring lawn treatment.

[mikkel]

Brian, did you see occasionally white kumquat seedlings, too.

I observe it on Yuzu seedlings. this year nearly 80% of all seedlings are white while other Citrus are green. Last year the same on Yuzu.

[Vlad]

What happens with the white seedlings? Are they healthy? Do they survive?

[mikkel]

They die after some time.

[Millet]

The white seedlings (albino seedlings) are unable to produce energy, because they do not have  chlorophyll, the chemical needed to manufactures energy from the sin light.

[Heinrich]

Ilya, yes, iron sulfate is a useful agent against moss. I have successfully used it on other occasions. However, if the environment doesn’t change, the moss will be back very soon. With citrus, I donīt regard the moss as a problem. When it finely becomes too dense, it is time to repot. As you can see on the photo with the kumquat cotyledons, the moss didnīt become too dense, within 3 ― years. Actually, I donīt even know, if these cotyledons have roots, or if they are just sitting in the peat and moss. Examining these cotyledons may be their end.

[Ilya11]

Albino seedlings in citrus are often due to seed coat infection by Alternaria  fungus.

[Millet]

Removal of the seed coat (testa) before planting the seed prevents albinism.

https://ucanr.edu/repositoryfiles/ca1203p7-64614.pdf

[Lory]

Lorenzo, sure most citrus seedlings grow like weeds in the tropics. However, it is not so easy in my climate zone. When I sow citrus, it is winter and it is cold. Inside the heated houses, light and humidity levels are low. Therefore, I bag the pots and put them on a heating map. Under such conditions mosses start to grow, often before the seeds germinate. Later, when the seedlings are uncovered and the conditions are much drier, the established mosses stay and give a wrong impression about the watering regime. These seedling are not overwatered. I could improve my results, if I give additionally artificial light, also. I didnīt use grow light technology yet, but may utilize it in the future.

Sorry for my judgement, i just evalueted what i could see from the pictures

[Heinrich]

Lorenzo, that is fine. Regarding the photos, I can understand your judgement.

[Heinrich]

Two weeks ago, one of my Meiwa kumquat cotyledons disappeared. This week, the second cotyledon died as well. Possibly, the soil was too wet, causing a fungus gnat infestation. The seeds were germinated in January 2015. The cotyledons reached an age of 2 years and 10 months. They neither produced leaves nor roots.

[Lory]

so sad to hear that.
Probably the mix of low temperature/overwatering/wrong soil was lethal.
It's unbelievable that in more than 2 years no leaves nor roots have grown! 

[Heinrich]

I have found it quite amazing, that a cotyledon, broken off from the seedling plant, can live by itself for such long time.

[SoCal2warm]

I've found the best way to germinate citrus seeds is to use a three step process. First sprout them wrapped in a moist paper towel in a sealed plastic bag. This may take about 1-2 weeks. Then carefully plant the sprouts  in a seed germination tray with a covered lid to hold humidity. Then after 3 or 4 more weeks the seedling will be ready to move into a plastic cup. If you use a clear plastic one it will be easier to gage soil moisture levels. (At this stage it may be best to keep the cups inside a growing tent enclosure to hold heat and humidity)

If you leave the seedlings in the germination tray too long many of them will start to suffer root rot because the soil is continually too moist. But this contained humidity also helps guarantee they survive and thrive in the earliest stage of their life. Another reason you can't leave them there too long is because there is limited soil area for root growth. Moving the seeds three different times takes a lot of work, and each time it's done it has to be done carefully, but it's the method that gives the best results and has the highest survival rates.

[Lory]

Here citrus seeds are among the easiest to germinate and grow.
Just bury them half inch (about 1cm) in a mix of good organic garden soil and fine river sand and water regularly to keep the soil moist but not too wet. No water logging is tolerated.
They grow quickly and healthy, these are lemons just 3 weeks after sowing




And this is 4 months later

[Vlad]

I have used the moist paper towel method successfully until recently when I ran into a problem with mold growth and had to transfer the seeds to seed starting medium.

[coyote]

I've germinated my citrus seeds by removing the seed coating and them treating them the same as I do tomato starts.  I start them in a seed tray in a soil-less medium with a heat mat and cover. I've had about 70 percent germination rates with no sickly seedlings this way.

These are two moro blood orange seeds I started two years ago.  I believe that one is nucellar and one is zygotic as they have different leaf shapes and growth patterns.