Good question, you could use something as simple as this https://www.amazon.com/Raindrip-R605DT-Filter-Fertilizer-Applicator/dp/B0007WO6C4/ if you have drip irrigation. Just fill the filter screen canister with water soluble fertilizer such as standard MiracleGro or MiracleGro tomato fertilizer. This is what I do. As for how much, you'll have to experiment, as with many things in gardening, I've learned. I'd start with a low amount of water soluble fertilizer, use low-flow drip emitters (0.5-2 GPH) but don't run the system for too long. It's probably not very effective, but worth a shot. I haven't been able to tell whether or it's an effective fert injection system since it is quite crude. I stick with granular fertilizers for the most part. With my clay soil which tends to hold onto the nutrients, I only have to apply the granules twice a year.

That's a cool little system, my only concern is trying to figure out how much fertilizer it dispenses. It looks like you can actually get fertilizer tablets that are meant for it. I'll look into it more, but in the mean time, I've just been using General Hydroponics flora series nutes. I make a 5 gallon batch and it lasts a while, just a lil time consuming. Not all my plants made it, so I'm only having to water 4 plants. I installed my drip system today, it needs a lil work, but until I have a final layout/design of my new garden area it works.

Kevin

You can get fertilizer tablets, but they are extremely overpriced, something on the order of ~$50-60 a pound, why on earth would anyone pay that much? What kind of soil mix are your tomatoes in, by the way? Is it hard to grow them in Florida?

I'm trying out the 511 mix that everyone talks about on the container gardening forum. It a mix of fine pine bark, perlite and peat moss ( 5:1:1 parts respectively). It is suppose to be really good, the only downfall is that you must fertilize it regularly, since it doesn't have much to offer in nutrients. That's why I asked about injecting fertilizer. I'm new at growing tomatoes, this spring I grew tomatoes in 5gal buckets with a mix of compost, soil, and cow manure. I had good results for a beginner. I got pretty lucky growing tomatoes up until about 2 weeks ago, when disease really started to plague my new plants. I start with about 20 plants nad I still have 4 of them, but they are battling grey leaf mold currently. I did have tomatoes on the counter for almost 2 months in all. My old plants are actually starting to set fruit gain so ill be good again soon.

Here's a couple survivors. I di have to move them around and I just trellised them the other day.

My garden at the beginning of the year

Nice garden, I'm having some good results with 5-1-1 for lemon trees and blueberries. Also good for acid-loving ornamentals like hydrangea and camellia. You're right, it needs to be fertilized often, but you could just work in slow release granular fertilizer into the top couple inches of mix. Good quality ones like Osmocote can last up to 6 months, but I've okay results with HomeDepot brand discount stuff. 40lb bag of citrus/avocado fertilizer for $19.99. I only fertilize once a month with DynaGro FoilagePro + vinegar and dynagro pro-tekt silicon (does seem to help with heat tolerance).

I'm not familiar with those products. I'll check them out. Do you think the protekt stuff works for preventing diseases. I live in a hot and humidity and wet location. Disease is something I'll always be battling. Be nice if that stuff works and helps prevent disease.

It might, it's still being studied:

https://hortcom.files.wordpress.com/2013/02/nutrifert_silicon-role.pdf

http://ipnc.ucdavis.edu/powerpoints/R313_0828_1450_Epstein.pdf

http://sebsnjaesnews.rutgers.edu/2013/03/silicon-an-essential-plant-nutrient-2/

I also use it to add an additional potassium source for plants that need it like my fig trees and hibiscus.