Struggling mango seedlings

[nexxogen]

Hello everyone.

I'm trying to grow some mango trees from seed as an experiment.

I live in Bar, Montenegro which is located in southern Europe and it has a Mediterranean climate with hot and relatively dry summers, and mild and rainy winters. The daily low can drop below freezing about 2 or 3 times a year (in January usually), though some years pass without a single day with temperatures below freezing point. I understand that these conditions are far from being perfect for growing mangoes, but as I said, it's an experiment to see whether I can get fruit with extra care.

I've tried growing several mangoes from seed, and all of them ended up acting the same way - after the initial leaves form and grow on the seedling, the growth almost completely stops. The plant tries to produce a new batch of leaflets but they quickly dry out and fall off. Once in a while, a plant manages to grow these leaflets into regular leaves, but that rarely happens. It's mostly this endless process of leaflets forming and then drying out before they get to grow into regular leaves. After almost two years, none of my mango seedlings are more than one foot tall. They are alive, but not growing.

Did anyone ever experience this? Maybe I should mention that none of the seeds I grew the plants from was polyembryonic, not sure if that matters. Maybe they don't have enough humidity? I'm really curious about what's happening, and I would really appreciate any sort of advice.

Thank you.

[shinzo]

Hi nexxogen,
I am from Tunisia, i have also mediterranean climate with probably hotter summer than yours.

I started my first mango from seed in may 2015, it grew the first set of leaves as yours and then failed to continue its growth during that growing season, it managed to survive the winter outside, but i think i killed it with overfertilization.

My second seedling from a kent fruit was planted may 2016 in a pot indoors, it shows the same symptoms as yours (still alive now).

My two last seedlings were planted from egyptian grown mangoes last september (indoors also). They grew better than the previous seedlings. They turned out to be polyembryonic seedlings. Yesterday, thanks to the help of the forum i discovered they were suffering from salt burn and i discovered also that there were some gnats larvae in the potting soil (which may have been damaging the root system and thus limiting the growth potential of all my  seedlings, you may want to check if you have the same thing in your pots). I am planning to plant them outside next week and i hope this time they will  outpass the step of the first set of leaves.
I hope this may help you somehow.

[nexxogen]

Hello shinzo.

Thank you for your answer. I don't think there are larvae in my soil. But what causes salt burn? The thing is, before I moved the seedlings to Montenegro, I've started them in Belgrade, Serbia (during warm months), which has a different climate. The symptoms were the same, and I hoped that would change after I move the plants to Montenegro, but it didn't.

[shinzo]

I am not an expert, but i think excess fertilizer and water quality are the causes (i don't know if there are other causes for salt burn).
For my case it was just the tap water wich caused the salt/mineral excess since i only fertilzed them once with nettle tea. I think tap water is not good for them, at least our tap water here in tunisia.
You can see the salt deposits on the outside of the pot and in the edges

[nexxogen]

OK, so what is then the alternative to tap water for watering the plants?

[shinzo]

Rain water if you can store some i guess, or well water.

[simon_grow]

If you can maintain the pH of your soil and water around 6.5, your trees will be much happier. Potted mango trees can often suffer from lack of micronutrients due to the need for watering which flushes the nutrients from the soil. Occasional foliar feeding can help with this. The soil should also be flushed with rain or Reverse Osmosis water to remove salt buildup in the soil. If you don't have good quality water, just use whatever you have. Flush with a couple gallons, wait an hour or two and flush with another couple of gallons, wait a couple hours and repeat one more time.


You can also set the potted plant in a bucket with several inches of water to help loosen the salts from the soil prior to flushing. With your last rinse, you can add diluted fertilizer for a drench to ionize the water and help remove salt buildup and to add some nutrients back to the soil.

When growing in pots, make sure you let the soil dry out between waterings, especially during cold weather. The seedlings can last a while without water and often times people growing mango seedlings water much too frequently. You want the soil at the bottom of the pot to be dry before watering again.
Bottom heat for mango seedlings will help the bottom of the pot dry up faster and also greatly increases the rate of growth if given proper light levels as well.

Simon

[nexxogen]

Thanks Simon for your answer.

When you say "flush", you mean just flood the pot with a lot of water? Do this 3 times in a day, but how often? Once a month?

Is there an easy way to tell if there's too much salt in the soil?

[pineislander]

It looks to like the pot size is very small and not very full with soil.

[simon_grow]

Thanks Simon for your answer.

When you say "flush", you mean just flood the pot with a lot of water? Do this 3 times in a day, but how often? Once a month?

Is there an easy way to tell if there's too much salt in the soil?

Sorry I missed your question, you only need to flush your soil every once in a while when you suspect there is a buildup of salts in your potting soil. About once every 2-3 months should suffice. Growing mango seedlings in marginal climates can be tricky as they hate the cold weather. My climate sounds like it's similar to yours, sort of, as I usually get a couple nights of frost every year or other year.

When the weather gets cold, you should avoid giving it ground applications of fertilizer and also cut back heavily on watering. Wet roots or wet soil on the bottom of the container during the Winter is very bad for the plants.

If you see salt build up in your pot around the top edge or towards the bottom of your pot where water tends to collect, that is a good sign you are beginning to have salt buildup and may have nutrient lock. You can mitigate this by foliar feeding, especially with micros.

I also agree that the pot size can be a little deeper. I did a lot of experiments with mango seedlings and when they first push out of the embryo, the tap root grows straight down for many inches until it hits an obstruction. It can easily push down 8 inches or more by the time it's first set of leaves turn green.

If your seedling is already in a pot, do not up pot it into a much larger pot. You need to gradually step up the pot size very slowly. I'm only recommending that you could have started off a new seedling in a slightly deeper pot. Bottom heat is a great thing as it will dry up the water that puddles in the bottom of the pot and the bottom heat accelerates growth. I use seedling heat mats which can be purchased online.

Simon

[simon_grow]

I got the posters mixed up and it Shinzo that I believe can use deeper pots and perhaps a flush of the soil.

For the original poster, if you get below freezing, it will be very difficult to keep mangos alive but if you have some seedlings that are already 2 years old, maybe you could do it.

Here's some pictures of my seedlings growing in pot, raised beds and in the ground. The seedlings planted directly into the ground perform much better for me and don't require flushing. They also have less chances of root rot because excess water dissipates into the surrounding soil.

Simon