Fertilising guide

How to fertilise Principe Borghese Tomato (Solanum lycopersicum 'Principe Borghese')— schedule & NPK

Also called Principe Borghese tomato, Italian drying tomato.

More about principe borghese tomato

About Principe Borghese Tomato

Solanum lycopersicum 'Principe Borghese' · also called Principe Borghese tomato, Italian drying tomato · edible

Principe Borghese is an Italian determinate heirloom prized for sun-drying. It bears heavy clusters of small, dense, 30-40 g plum-shaped fruit with little juice and few seeds, concentrating flavour when dried. The compact bushy plants set a large, fairly concentrated crop and need only modest staking over a roughly 75-day season.

Growth habit: Determinate bush; compact, self-limiting, sets most fruit in a concentrated flush; benefits from a short cage or stake.

What fertiliser principe borghese tomato actually wants — and why

Principe Borghese Tomato feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

For the language behind the three numbers on the bottle — what nitrogen, phosphorus and potassium each do — see the NPK ratio explained entry. The short version for principe borghese tomato: match the feed to the job the plant is doing right now, not to a generic “plant food” on the shelf.

How often to feed principe borghese tomato, and which months

Feeding only earns its keep while the plant is in active growth and can use the nutrients — pour feed into a dormant or low-light plant and it simply builds up as root-burning salt. For principe borghese tomato:

Apply compost at planting, then a high-potassium tomato feed every 14 days once fruit set. Being determinate it crops over a shorter window, so avoid late heavy nitrogen that pushes leaf over fruit. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

The dormant-season rule matters more than the exact interval: skip feeding entirely when principe borghese tomato is resting. For the wider context on indoor feeding rhythms across the seasons, the houseplant fertiliser schedule walks through the year month by month.

What strength to mix for principe borghese tomato

Follow the crop-feed label rate for principe borghese tomato — these are calibrated for hungry vegetables. Consistency through fruiting matters more than strength; erratic feeding causes problems like blossom-end rot.

Feeding always goes onto already-damp soil, never dry roots — water principe borghese tomato first if the soil is dry, then apply the diluted feed. The companion question is when to water at all, covered in the principe borghese tomato watering schedule.

Signs you are over-feeding principe borghese tomato

Over-feeding is far more common — and more damaging — than under-feeding for most plants. The classic tells for principe borghese tomato:

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen).
Lush foliage hiding the crop; soft growth prone to pests and disease.
Salt crust on the soil and scorched leaf edges in containers.

Signs you are under-feeding principe borghese tomato

Pale, yellowing lower leaves and stunted growth.
Small fruit, poor set, and a quickly exhausted plant.
Blossom-end rot and weak cropping from erratic or insufficient feeding.

If the symptoms point at watering, light or roots rather than nutrition, the full principe borghese tomato care brief covers soil, humidity and the common problems for this species.

Flushing and leaching the salts

In containers, fertiliser salts build up fast — water principe borghese tomato thoroughly so excess drains from the base each time, and flush pots with plain water every few weeks to prevent a damaging salt build-up.

Organic vs synthetic feeds for principe borghese tomato

Organic options

Garden compost or well-rotted manure dug in before planting, plus a liquid comfrey or seaweed feed once fruiting starts. UK: comfrey feed or organic Tomorite; US: Espoma Tomato-tone or Neptune's Harvest. Builds soil and feeds in one.

Synthetic / liquid feeds

A balanced feed at planting then a high-potash tomato feed in fruiting — UK: Growmore at planting then Tomorite (Levington) or Phostrogen; US: a balanced 10-10-10 then Miracle-Gro Tomato or a bloom booster.

Brand names are examples, not endorsements, and UK and US ranges differ — check the label’s own NPK and dilution rate, since formulations change.

Fertilising principe borghese tomato — frequently asked questions

What fertiliser does principe borghese tomato need?

Balanced (even N-P-K) at planting for roots and frame, then switch to a high-potassium ("high-potash") tomato-style feed once the first flowers open — potassium is what sizes and ripens fruit, not nitrogen. Principe Borghese Tomato feeds in two distinct phases — balanced to build the plant, then high-potassium the moment flowering starts to set and fill a heavy crop.

How often should I feed principe borghese tomato?

Apply compost at planting, then a high-potassium tomato feed every 14 days once fruit set. Being determinate it crops over a shorter window, so avoid late heavy nitrogen that pushes leaf over fruit. Apply compost at planting, then a high-potassium tomato feed every 14 days once fruit set. Being determinate it crops over a shorter window, so avoid late heavy nitrogen that pushes leaf over fruit. So: a balanced feed or compost at planting, then a high-potash liquid every 1-2 weeks from first flower through harvest across the main season (spring through early autumn).

What strength of feed for principe borghese tomato?

What does over-feeding principe borghese tomato look like?

Vigorous dark-green leafy growth but few flowers or fruit (excess nitrogen). Lush foliage hiding the crop; soft growth prone to pests and disease. Salt crust on the soil and scorched leaf edges in containers. Staying on a high-nitrogen feed once principe borghese tomato starts flowering is the classic error — you get a huge leafy plant and a disappointing crop. Switch to high-potash the moment flowers appear.

Should I flush the soil of principe borghese tomato?