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New leaves in center of sunflowers are yellow

Sunflower    Karachi, Pakistan

Sunflower type: Velvet Queen
My Plant Journal: https://www.plantvillage.com/gardens/...

This will be a little long to read so please have patience.

I have been growing these velvet queen sunflowers from seeds but yesterday I noticed that the centers of the plants are are a bit yellow. My guess is either nitrogen deficiency, since I decided to simply use the soil I got from the nursery which is basically manure based compost with sand, or it could be excess watering even though the pot drains out in about a couple of minutes and all you can see is wetness but never any standing water, and I have been watering in the evening when the sun is about to set.

I have reduce the amount of water I give to these starting today but yesterday I also added some dried leaves (browns) making an error in composting basics. Yellowing leaves could be due to lack of nitrogen so for that I should be adding the greens. But before I did tried anything further I wanted to seek guidance here regarding how to handle this situation.

Now on to the types of compost I have. Nurseries here aren't familiar much with the concept of composting so they only sell manure based compost with sand. There are two that I have; Compost 1 (photo attached) is a bag that was manure based compost with lots of tiny white composting bugs luckily swarming overtime, these have eaten through everything whenever I added them to my previous pots with the addition of new browns and greens compostable goods. And recently I added a lot of ground green tea bags into this bag, spices like used cinnamon sticks and old coriander seeds and what not for greens and dried leaves for browns and the bugs seems to be crawling in the bag and composting everything down. Compost 2 (photo attached) was a shot at starting a compost bucket back in March with fruit scraps, shredded cardboard, newspaper and dried leaves with startup compost sprinkle from the Compost 1 (back in those days to introduce the micro-organisms), I never really tumbled it much as recommended but kept adding water whenever it'd dry up. A week ago I actually noticed melon seeds from the fruit discards sprouted in this compost along with sprouts of some other seeds so that actually got me excited that my compost was ready plus the earthy smell that I had only read about in guides until now. There are all sorts of crawling bugs like beetles akin to those I have seen in other people's compost videos and maggots still decomposing the pile in the bucket.

Now on to my question, what steps should I take to help the yellowing leaves on these sunflowers, and if I shall add compost which one should I use?

Another issue that's came up recently is shown in the second photo with highlighted parts; the tips of these leaves are turning brown and crisp. Is this normal?


Posted by: Naveed (6 points) Naveed
Posted: August 4, 2015




Answers

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First off, the centers of the plants look completely normal. It is just the new growth which will darken naturally as the new leaves mature. Nothing to worry about. I would be very surprised if you have a nitrogen deficiency given that the compost is manure based. The browning leaf tips can be caused by a few things but in your case, I think it may be caused by the soil. I would recommend transplanting the plants into the compost you produced yourself and see how they get on. Keep up with the daily watering as it will help salts to leach from the soil. Also, if I may recommend that you switch your schedule from evening to morning. Watering at night when the sun is setting reduces the time the plants have to dry as the temperatures drop when the sun is setting. This in turn promotes diseases such as mildews which thrive in cool, wet conditions. Water early so that plants have plenty time to dry


Posted by: Lindsay McMenemy (167 points) Lindsay McMenemy
Posted: August 5, 2015


Naveed commented,
Thanks for you reply Lindsay. I guess I am noticing very minor things.
I won't be able to transplant now, that gives me the creeps considering I germinated these babies into the very same soil and the fact that sunflowers don't like transplantation, unless you mean that I sprinkle some of my compost around the plants which I was actually considering doing sometime along the way.
As for watering in the morning, I started watering in the evening to promote absorption and not letting the sun dry off. And in the morning I am on a run so can't find time to water in the morning however, what if I start watering before sleeping at around 12am-1am? This will be comparatively closer to sunrise. What I have also been observing is that from 8pm till 11pm, the plants actually loosen up and hang the leaves down indicating a sleep session maybe? So after they wake up pumped up at 11pm they should absorb the water more efficiently.

almost 4 years ago.

Naveed commented,
The yellow centers seems to be blending in with the green leaves (check new photo). You were right Lindsay, the plants seem to be doing fine. In fact, they have grown much bigger since this post. I have amended the soil with some of my home made compost as well today.
almost 4 years ago.

Lindsay McMenemy commented,
Excellent, glad to hear it!
almost 4 years ago.



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