Well, what does the bag say, or if you don't have the bag, what does their website say? If it doesn't have ferts then get something recommended for tomatoes and follow the instruction on the package. It really is as simple as that. Sometimes container soils contain a product that retains moisture which is very helpful. If your product doesn't have that then you'll need to keep a closer eye on the moisture. Toms in containers do best if they're not allowed to dry out and conversely, that the soil isn't a bog.

Hello Patsyann,

I Googled Sunshine #4 and it appears it doesn't contain fertilizer: Ingredients Formulated with Canadian Sphagnum peat moss, coarse perlite, organic starter nutrient charge, Gypsum and dolomitic limestone. Their site also says Sunshine #4 Natural & Organic is recommended where high air capacity and fast drainage are needed: during winter months, with water and salt sensitive crops, or where frequent leaching is required. Which means it probably doesn't retain water and will need to be watered frequently.

Until your tomatoes go into their final tubs, they should have enough nutrients from the potting soil when you pot them up.

Plants that are grown in any kind of container will need feeding more often than plants that are grown in the ground because each time they are watered, the water run off carries away vital nutrients. As such many people who grow in containers fertilize with a dilute solution of a liquid fertilizer. How much and how often is usually subjective and somewhat due to personal preference. Some use a 1/4 strength of a balanced fertilizer drench on a weekly basis, others go 1/3 or 1/2 strength but less frequently depending on how their plants look. OTOH, if you over do the nitrogen, you will wind of with lots of leaves and very little or no fruit.

You may want to take a look over in the container forum and see what the people who are very experienced on growing in containers have to say about your growing medium.

Betsy

Here is a link that might be useful: Container Gardening Forum

If you are moving your plants to a mix that has no fertilizer, I would add diluted fertilizer 2 weeks after transplanting and continue on a 2 week schedule.

Plants do need fertilizer to grow and be healthy but they don't need a lot when they are small.

You can use a neutral fertilizer, meaning that the numbers - NPK - are all the same. For example, 5-5-5 which won't hurt your plants a bit. Do watch out for adding too much nitrogen (N-or the first number) as you would wind up with very wonderful foliage and little to no flowering which becomes the fruit/veggie. NPK being 5-10-5 would be OK especially sincer the higher number is phosphorous which tomatoes need for the best fruiting.

I grow tomatoes in containers and generally feed twice during the season - once when planting out and again in mid-season. I also avoid over-watering as that is how the fertilizer is depleted. It will depend on your watering methods and the type of fertilizer you use.

Since you have already had trouble finding the soil you used last year, you might want to check your garden center and see what they have and ask questions about its use. They are usually very helpful.

Thanks for the input. I think I'm out of luck with the Sunshine Mix as we have hardly any rain during the summer and I rely on a drip system with limited water in the well during our growing season. It is more for the transplanting into their first an second containers that I need a mix. Other than that, I will plant them out in the soil I used last year with some amendments.

Do watch out for adding too much nitrogen (N-or the first number) as you would wind up with very wonderful foliage and little to no flowering

That's what you want in the early stages. You don't want a stem with fruit!

Sounds reasonable logic, TAZ, but it often backfires on you and you can easily overfertilize nitrogen to young growing plants. Fruiting plants need more nitrogen and Potash and they can handle the extra fertilizer as bigger plants.

Sounds like you have a good mix.
I do not plant in pots,(have 1600 sq.ft.plot). I am going to try Aozmite this year. If the bag size is to large, try real salt(bran name on eBay)in smaller size.
This is sea minerals ,volcano ash, 60 natural elements.
I think it will help the over all mineralization of my sandy soil. N-P-K are 3 of 20 elements our plants need to be top performers.
Sorry, I will get off my tomato box now.

I think your Sunshine 4 is a better product than Miracle Gro. You may need to water a little more, but your plants will be healthier. The key for tomatoes is to use large containers, at least 15 gallons. I have grown tomatoes in large containers for many years. They are heavy feeders. I've had the best results by adding a controlled release fertilizer to the soil before planting and also using a soluble fertilizer every couple weeks once the plants start producing fruit. I used a version of Osmocote that has all the trace elements. This year I plan to use a new Miracle Gro timed release fertilizer called Shake and Feed for Tomatoes. It includes calcium, which is helpful in preventing BER, as well as all the other trace elements.

Thank you Ohiofem. I had muscled the Sunshine 4 back into the pickup and now will muscle it back into the potting shed (nee:laundry room). Will phone around to see if I can buy the other fertilizers you recommended.
So nice of you all to share your knowledge.

Fruiting plants need more nitrogen and Potash

Fruiting plants need more phosphorus and potassium than nitrogen IME.