There are so many factors involved in gardening it would be hard to actually determine the exact problem this way/Y!A.
1.Most vegetable gardens require FULL SUN which means 6 to 8 hours of sunlight each day.
2. Lack of water or too much water....my suggestion is buy a/ See Below either one or even both this will help you in determining just exactly what you need these can also be learning tools to help you better understand just by looking and touching the soil.
AS FOR FERTILIZER.....you pretty well can't go wrong with foilage fertilizing/Miracle Gro or
Peters Plant food. Like with all things it can be over fertilized and you wind up with the plants and not the fruit.
PS.............Cucumbers will produce male and female blossoms/the twain will produce cucumbers.
GOOD LUCK!
......Soil Moisture Tester for Plants
PRICE:$18.99
http://www.cleanairgardening.com/moisture.html
........Soil PH Tester
PRICE:$19.99
http://www.cleanairgardening.com/phtester.html
.........Soil Test Kit
Soil Test Kit - $15.99
http://www.outsidepride.com/store/catalog/Soil-Test-Kit-p-16341.html

Why is monitoring your soil important?
http://www.cleanairgardening.com/soiltester.html
A successful garden starts with the right soil conditions, because all plants have their preferred growing conditions.
The soil pH level will affect how well plants utilize the total nutrients available in the soil. These nutrients are the building blocks the plant requires for successful growth.
Successful growth cannot be achieved with inadequate or improper light amounts.
And even if these three growing conditions are ideal, a garden will not thrive if it is over or under watered.