More plants are killed, stunted, burned or otherwise harmed by over fertilizing than by underfertilizing.
When the weather is hot plant growth slows and that's even more reason not to fertilize.
I used to be a deamon with the Mirical Gro....but once I burned a planter of petunias.....and someone suggested that bagged composted manure is safer.......and I now just ues that....and alfalfa pellets and all the compost my leaves and grass will make.
But...I do know people who add just a tiny bit ( about 10% of an application) to the water every time they water their pots.....and they are wonderful....soooo.
But whatever you choose.....very very little fertilizer when it's hot.
Linda C

Very important for plant health: Never fertilize a dry plant (with a liquid fertilizer solution).

Different plants prefer different fertilizers, too. Generally, foliage plants will be happy with a higher nitrogen content while the same fertilizer applied to flowering plants can cause lots of vegetative growth at the expense of blooms. Attempting to achieve maximum growth by fertilizing at the limit is usually not the best way to a happy, healthy plant.

Al

Good advice Al. For my flowering plants, veggies included, I use a fertilizer that has the middle number the highest...that's for blooms. For my plants in the ground I fertilize once a month with a liquid fertilizer. I do full strength for those. For my pots I do it every 2 weeks. I do the full dosage they call for. Potted plants will need it more than the ones in the ground, so much runs out.
Good luck!

Kat

Thanks Al and Linda for getting back to me. I would have harmed my plants instead of helping them. After all the time spent getting them where they are now I would have been sick to loose them. I will be very careful with the fertilizer.
Thanks again!!

I fertilize only plants in containers. I use time release balanced fertilizer and compost tea. The soil in the garden is composted(about 2 inches compost added) twice yearly and after about 3 years no fertilizer is ever added. Al

I do what Calistoga does - I fertilize only the container plants. When I pot them up in the Spring, I always make sure I'm using fresh potting mix, not whatever was left in the pot from last year (potted plants deplete the nutrients in the soil very quickly, so it's not a good idea to reuse old soil). Then I toss some Osmocote into the pot with the potting mix, and that's it.

If they're impatiens, I don't use anything, except fresh potting mix (not soil, mix). I fertilized them once, and I had nothing but rich green foliage for about 2 months! I'll never do that again...

Also a no fertilizer compost alfalfa kind of gardner.
Linda C

I have seldom changed the soil in my pots. I leave my pots out in one of my gardens by the deck. The roots from the old plants decompose and enrich the soil. Since my pots are sitting on the ground, I end up with worms inside which also help. I have too many pots to replace soil every year. I always mix the soil up before I add plants though. For 5 yrs now the plants have thrived. I use a 10-15-10 fertilizer for my flowering plants. Not too much to over fertilize, but enough to give a boost and look good.

Kat

(got this advice from a greenhouse man who was 80 years old, and grew potted flowers)

If you have the urge to fertilize often, use a balanced organic fertilizer such as a 1-1-1 fish emulsion. Plants don't like heavy fertilizer application, it stresses the system.

I use this diluted at quarter strength every week, and all my plants have steady growth and thick lush blooms for the past years.