Question
My jalapenos plants did not grow very big, about 8 inches tall, they bloom and give peppers, but the peppers stop growing after an inch or inch and half at the most... Whats going on? my buddies grow several feet high and give 4 inch peppers

Answer
It sounds like a problem with your soil. Either the ph level is out of balance or you are lacking specific nutrients, such as phosphorus, for good growth.

Phosphorus is the second number on the fertilizer package. This nutrient is essential for large fruit and an abundant harvest. Avoid fertilizers high in nitrogen (the first number) since these tend to promote lush foliage and small fruit.

To neutralize the ph, you either have to add lime or sulfur depending on the level. If it is below 7.0, it is too acidic and needs lime. Over 7.0 is alkaline and needs sulfur to correct. You can purchase a ph test kit at most garden centers for an accurate reading. To stabilize ph levels going forward, you must add organic materials to the soil, such as peat, manure, or compost. These amendments will also provide nutrients to the plants and improve drainage.  

This leads to one other possibility, which is poor drainage. Peppers, unlike the other vegetables you are growing, require very little water. They prefer the soil to dry out between waterings. If the soil does not drain, the roots become saturated and cannot draw in the nutrients needed for healthy growth. The organic amendments will correct this issue. These materials also contain microorganisms that will ward off disease and pests.  

I hope this answered your question. Please write again if you ever need assistance.  

Regards,  

Mike