Pale Zucchini Leaves
I have some zucchini and summer squash planted in cat litter buckets. They are about a month in (the zucchini from little transplants and the squash from seed) and have just started producing, but the oldest leaves are starting to turn pale and eventually die. They are still blooming and everything fine, but if the problem is something I can fix, I want to try to catch it before it gets too bad. I know these containers are small for zucchini. I would have preferred something larger but I do not get enough sun in my little apartment patio and have to keep them "transportable" in the shared courtyard behind. From everything I have read it seems to be one of three things: too much nitrogen, too little nitrogen, or just unhappiness with the small container. here is all the background info (sorry that it is a novel!):
I planted them in a mix of fancy top soil (had some peat in it), coconut coir from my tarantula cages, rabbit manure, and oak leaf mold with some bone meal, egg shells, rinsed sea-weed, Epsom salt, and hermit crab food (because it is composed mainly of brine shrimp and sea-weed meal) mixed in. The containers each have two drainage holes 3/4 across about 2" up from the bottom.
Since planting, I have been fertilizer with nitrogen-only (9%) MG organic fertilizer about every 8-9 days (package says week to 10 days) at 3/4 cap per 3-4 gallons (package says 1/2 cap for 2 gallons). They get almost a full day's sun and it has been hot (mid 80s) the past couple of weeks here in central Florida. About 2 weeks ago, we had some torrential rains for a couple of days (over 4 inches a day), and I was concerned that the nutrients might have flushed out.
It was about 1.5 weeks ago that I started noticing the pale coloring (whole plant but stronger going down towards the older leaves). Some of the leaves also have a very faint burn 1/8 to 1/4 inch in at the side edges. At this point, I have been watering the large zucchini plant 1/2 gallon a day (at least) when I can pick it up and it feels light. Because the container is so small for the size of the plant and the weather is so warm, I try to check it multiple times a day and water small amounts to keep it consistently moist. I rarely see much water come out the drainage holes. After doing research, I came to the conclusion that all this watering (and maybe the started zucchini production as the smallest plant that is not producing yet is the greenest) was depleting the nitrogen (the veins are either normal or too light - not dark). So, the past couple of days, I have been fertilizing with an extremely diluted amount (1/4 teaspoon or so in half a gallon) every time I water (which is every day). Now, I'm a worried that either it actually has too much nitrogen or the problem is just the container size. Photos are below starting with young plant. Any thoughts?
One week after transplant
About a week and half ago - you can see paleness starting to form in newer leaves here
Older Leaf on Current Plant
Younger Leaf on Current Plant