No one can answer that question w/o first knowing what is already in the soil, and established trees often don't need fertilizer. If you plan on taking the 'shotgun approach' any fertilizer in a 3:1:2 RATIO will come closest to providing nutrients in the same RATIO the plant uses. Don't confuse 'ratio' with the NPK %s. E.g., 24-8-16, 12-4-8, 9-3-6, are all 3:1:2 RATIO fertilizers, while 20-20-20 and 12-12-12 are 1:1:1 RATIO fertilizers.

Al

Al,

Thanks for the info.

I haven't done a soil test, so I don't really know much about the soil (it looks dark and healthy). I planted the tree in the beginning of May. I had it in a container for 2 years before that. I treated the hole with a mixture of cow manure, peatmoss, and compost when I planted it.

I'm sure the tree will grow well based on the site and the soil preparation, but I was wondering if there is any fertilizer I can give it to encourage fruit production. I was thinking about giving it a more balanced 1-1-1 ratio fertilizer, hoping that would encourage it to fruit.

Any suggestions out there for a good fertilizer choice?

Joe

This chart I put together shows how plants use nutrients. I gave Nitrogen, because it's the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19 (16) 1/6
K 45-80 (62) 3/5
S 6-9 (8) 1/12
Mg 5-15 (10) 1/10
Ca 5-15 (10) 1/10
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06

You can see that a 1:1:1 ratio fertilizer supplies 6 times more P than a plant can use, and almost twice as much K. 3:1:2 ratio fertilizers, when multipliers of .43 and .83 are applied to the %s in the 3:1:2 ratio fertilizers to adjust actual P and K %s supplied (because P is 'reported' as P2O5 and K as K2O so the actual amounts of the elements supplied is considerably less than the %s reported), you'll see that the fertilizers with a 3:1:2 ratio supply nutrients in almost EXACTLY the same ratio as the plant uses. Your plants - your call. I just wanted to be sure you understood. ;o)

BTW - it's considered bad form to amend your planting hole with organic materials like manure, peat, compost. These materials will totally disappear within a few years and leave a hole. It's also likely you've created the 'bath tub effect', unless your soil has very good drainage. Water will tend to flow into and accumulate/remain in your planting soil in clay/clay loams until the percolation rate allows it to move downward through the soil.

Al

Al,

Thanks again for the info.

But I was wondering, if every plant uses nutrients in the exact same amounts, then why do fertilizer companies sell different types of fertilizers for different plants? For example, Miracle-Gro has a rose fertilizer that is 10-10-10 and a vegetable/tomato fertilizer that is 18-18-21. It seems that plants that produce flowers or fruit need higher amounts of P and K than plants grown just for foliage. Therefore I was thinking that a fig tree would need higher levels of P and K to encourage healthy fruiting. Ray Givan says to use a balanced fertlizer like a 6-6-6 or an 8-8-8 in "The New Fig Booklet" that he published in 2007. That's why I started this post to see what fertilizers guys are using out there with success to support good fruiting.

Joe

Sorry, but figs aren't THAT much different than any other plants/trees. It may not be as large a consideration for trees planted out, but it IS a consideration, and a considerable consideration for trees in containers. Supplying more of any element a plant uses than it needs unnecessarily raises the EC (electrical conductivity) of the soil and the TDS (total dissolved solids). These are ways of measuring total soil fertility. The lower these numbers are, the easier it is for the plant to absorb water and the nutrients dissolved in water. It's best to keep fertility levels low, but still in the adequate range.

When any one nutrient is supplied at higher than necessary rates, it not only does the plant no good, but it makes it more difficult for the plant to absorb water and nutrients, and can cause antagonistic deficiencies of other nutrients. Since you mentioned P, I'll share that evidence of phosphate over-fertilizing usually always includes some degree of leaf chlorosis. P competes with iron (Fe) and manganese (Mn) ions for attachment sites and causes antagonistic deficiencies of these micro-nutrients. Unfortunately, the deficiency of these elements causes interveinal chlorosis (yellowing), and the first thing we normally consider as a fix for yellow leaves is more fertilizer, so we give the plants a good dose of our favorite fertilizer which caused the chlorosis in the first place which causes, no surprise - worsening of the condition.

Even if your wish is to reduce N supplied relative to P and K by using a 1:1:1 fertilizer, it still supplies more P than needed compared to K. It makes much better sense when you want to reduce N and still keep P and K in a favorable ratio to supply a 3:1:2 ratio fertilizer at reduced rates and supplement only the K by adding a little potash to the soil or using a K supplement like Dyna-Gro's ProTeKt 0-0-3.

Al