“There are always so many questions about fertilizing.  I would like to go over some of the basics, especially since early spring can be a key time for taking care of fertilizing needs. Always ask yourself:
The type of plant you are focusing on (perennials, annuals, vegetables, ect).
What type of fertilizer to use based on season and the plant(s) you’re fertilizing.
When do you apply fertilizer?  Spring, Summer, Fall, Winter?
Where is the best place to apply fertilizers?  Topically or to the root zone?
Why is this necessary?  What are the benefits of fertilizing?

Since we could write a book on everything mentioned above let’s keep it brief and relevant to what we should focus on in early spring.  This is a great time of year to focus on perennials.  Most perennials prefer a well-balanced or all-purpose fertilizer (all three numbers on the packaging are identical, i.e. 3-3-3 or 16-16-16).  Perennials fed in early spring develop strong root systems which in turn produces larger, healthier plants.  Apply granular fertilizers to the soil around the root zone.

For annuals that are tough enough to be outside early and continue blooming throughout the summer, like petunias and verbena, apply well balanced or slightly higher nitrogen fertilizers. This gives them an extra boost, encouraging growth.  You can successfully use either a granular or foliar fertilizer.  Foliar fertilizers tend to react faster than granules since they are taken up by the plant through the leaves but need re-application more often.  For annuals I like to use granular fertilizer applications in the spring and start using weekly or biweekly applications of liquid fertilizer in the summer. Remember as a rule of thumb – ALWAYS apply fertilizers in the morning. It is less stressful for the plants.

Vegetables are a completely different beast when it comes to fertilizing.  There are numerous techniques when it comes to fertilizing your vegetables.  If it’s grown for leafy greens then apply fertilizers heavier in nitrogen. If it’s grown for the fruit apply fertilizers heavier in phosphorous.  Nitrogen promotes healthy, green foliage and too much of it can discourage fruit development while phosphorous promotes bud and flower growth which encourages more fruit.

When in doubt about fertilizing don’t hesitate to ask a fellow gardener. Some of the best advice is the advice that we share with each other!”

Source: http://AshlandGreenhouses_April2014Newsletter