I have a lemon cucumber plant sharing an Earth Box with a yellow crooked neck squash. The lemon cucumbers are bitter. They are round and yellow when picked. The plant is watered into the water reservoir every day. Because of the small ground space of the earth box its self, the plants are given miracle grow twice a week.
Ewww... no wonder they're bitter. That seems like way too much food.
Also unless the Earth Box is really tiny, holding very little soil, daily watering might not be necesssary. Long, slow watering is best, perhaps 2-3x/week. All this without knowing the size of the box and the amount of soil. Enough sunshine?
HB
Earth boxes have relatively little soil and the roots sit in the water beneath.
With cukes and squash, there is a lot of surface leaf and in a sunny location, the box would likely need water daily.
Lemon cukes can be tricky to gauge as ripe, so the OP might want to try picking them a bit earlier, before the full yellow emerges. It also cuts down on the seed/flesh ratio which can get out of hand with the lemons.
Any cuke crop can produce a bitter fruit once in awhile, and I have gotten a plant or two that just proves nasty once in a great while.
Insofar as the amount of Miracle Grow, it really depends what kind you are using, and at what strength. Generally, though, an Earth Box has a dry fertilizer laid down in a stripe on top of the soil at planting time. Check the instructions online.
Boron
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