Question
The growing season in my part of Montana is short, so I'm trying to grow tomatoes in an indoor greenhouse.  My tomato plants grow well, but the fruit is small and shriveled.  What to do?

Answer
Gail, when tomatoes are small, it is usually a result of excessive nitrogen and insufficient phosphorus in the soil, or excessive watering.

Phosphorus is essential to a bountiful harvest and large fruit. It is the second nutrient listed on fertilizer packages. Nitrogen, on the other hand, the first number listed, promotes lush foliage, but at the expense of a good harvest. Nitrogen is fine for lawns and lettuce, but is not recommended for fruit-bearing vegetables.

Secondly, be sure you are not over watering the soil. Doing so depletes the soil of nutrients and water logs the roots. The roots cannot absorb oxygen and nutrients when continually soaked.

In summary, purchase a fertilizer recommended solely for fruit-bearing vegetables such as tomatoes and peppers. The ideal NPK ratio on the bag is 1-2-2; i.e. 5-10-10. The 5 would stand for the percentage of nitrogen relative to the phosphorus (10) and potassium (10) ratio of the product. Only fertilize every 10 days and supplement the soil with as much organic matter as possible; i.e. peat moss, compost, or manure. Also, allow the soil to thoroughly dry between watering. These two steps should help promote larger fruit and a more abundant harvest.

Good luck, and please write again if I can ever be of assistance.

Regards,

Mike