Tomato Growing Calendar

January — Planning and preparation

What to do

• Decide how many plants you want and choose varieties for flavor, fruit size, and disease resistance.
• Check last year's seed: is it well stored, dry, and undamaged?
• Write down where tomatoes (and potatoes, peppers, eggplants — they are in the same family) grew last year, and plan a new spot for this season.
• Clean and wash the pots, trays, and tools you will use for seedlings.

Why

A lot of later problems — disease, weak growth, leggy seedlings — start with the containers, the potting mix, and the location. Now is the cheapest time to avoid them.

Common mistakes

• Reusing unwashed containers from last year.
• Planting tomatoes in the same spot as last year.

Tip: Keep a short season diary: variety, sowing date, planting date, problems. Next year it will be your most useful calendar.

February — Potting mix and light

What to do

• Prepare a light, well-drained mix for seedlings — not heavy garden soil — and moisten it before filling the pots.
• Find the brightest spot (a sunny window) or set up supplemental lighting: seedlings need 12–16 hours of light a day.
• If you don't have good light, don't rush sowing — a month later is better than leggy seedlings.

Why

The root is the foundation of the plant. A heavy or waterlogged mix limits the roots and creates problems that fertilizer won't fix later. And too little light is the main reason seedlings stretch.

Common mistakes

• Using old garden soil for seedlings.
• A warm but dark spot for seedlings.

March — Sowing and germination

What to do

• Sow seed roughly 6–8 weeks before you plan to plant out. For most of Bulgaria that means mid to late March.
• Keep a room temperature of about 21–24°C (70–75°F) until germination.
• After germination give plenty of light (12–16 hours a day). Keep the lamp close above the plants and raise it as they grow.
• Water moderately and in the morning; water should not stand in the container.

Why

High temperature with weak light stretches seedlings. A brighter, moderately warm spot gives sturdier, thicker stems. Overwatering sets up rot in seedlings.

Common mistakes

• A warm, dark spot for seedlings.
• Overwatering — a constantly wet mix.

Tip: A gentle air movement (without a draft straight on the plants) helps stems get stronger.

April — Potting up and hardening off

What to do

• When the first true leaves appear, move seedlings into larger pots. Tomatoes can be planted deeper: extra roots form along the buried part of the stem.
• Start hardening off 1–2 weeks before planting out: a few hours in shade and out of strong wind first, then gradually more time and more sun.
• Don't overfeed — extra nitrogen gives soft, overly leafy growth.

Why

Seedlings moved abruptly from indoors to strong sun and wind can sunscald or snap. Gradual adjustment is the cheapest insurance.

Common mistakes

• Moving seedlings straight into full sun.
• Feeding "to catch up" instead of providing more light.

Tip: If a seedling is leggy, plant it deeper — the buried stem will root.

May — Planting out

What to do

• Plant when frost risk has passed, nights are consistently warmer (usually around 10°C / 50°F or above), and the soil has warmed up.
• Plant deeper: strip the lower leaves and bury part of the stem.
• Water thoroughly after planting, then keep moisture even. Skip nitrogen for the first days.
• Set stakes or supports at planting — adding them later is harder and can damage the roots.
• Mulch to hold moisture and keep soil from splashing onto the lower leaves.

Why

After planting, the plant first rebuilds its roots. Cold soil and too much water stall growth for weeks, and early nitrogen slows rooting.

Common mistakes

• Planting into cold soil out of impatience.
• Watering a little every single day.

Tip: Water at the base, not over the leaves, and in the morning so foliage dries quickly.

June — Growth, flowering, and fruit set

What to do

• Tie plants to their supports and remove side shoots (on tall varieties) — that opens up airflow and saves energy for fruit.
• Water evenly, at the base and in the morning, so leaves dry quickly.
• Feed moderately with a balanced fertilizer. Too much nitrogen gives lots of leaves and little fruit.
• Look over the leaves regularly: catching spots or yellowing early matters.

Why

June is the most sensitive month: flowers set fruit only if the plant is not stressed. Wet leaves and dense foliage make disease easier, so airflow and dry leaves are the best protection.

Common mistakes

• Nitrogen when fruit set is poor.
• Watering the leaves in the evening.

Tip: If you notice spots or yellowing, see the guides for brown spots and yellow leaves on tomatoes below.

July — Peak fruiting

What to do

• Keep moisture even. The key July rule is that water should not swing between drought and flood.
• Mulch holds moisture. Keep leaves that shade the fruit and do not strip the plant bare.
• Pick often, as fruit ripens.
• Remove fruit with a black, leathery patch at the bottom (blossom-end rot) so they do not drain energy from healthy ones.

Why

Blossom-end rot is not a contagious disease; it is a problem of getting calcium to the fruit, most often from uneven watering. Water carries calcium to the fruit, and when water is lacking the calcium doesn't arrive.

Common mistakes

• Rare, very heavy watering after a dry spell.
• Stripping most of the leaves.

Tip: Water deeply when the top layer starts to dry, instead of a little every day.

August — Flavor and quality

What to do

• Keep watering evenly. A sharp dry-out followed by heavy watering can lead to cracking and blossom-end rot.
• Do not feed nitrogen: now the plant should fill and ripen fruit, not build leaves.
• If leaves yellow or fruit ripens poorly, do a soil test before adding fertilizer.
• Pick often and don't leave overripe fruit on the plant.

Why

Potassium supports fruit quality and ripening, but adding it blindly can block uptake of other nutrients. It is better to measure than to guess.

Common mistakes

• Nitrogen late in the season.
• Fertilizing without a test.

September — Late harvest

What to do

• Watch the forecast for frost and early cold.
• Many gardeners pinch the tops of tall plants about a month before the expected first frost, to direct energy to fruit that's already set.
• Before frost, pick the unripe green fruit too — they ripen indoors, somewhere warm.
• Nights get damper and cooler: keep airflow good and avoid wetting the leaves.

Why

In cool, damp weather disease develops faster and fruit hardly ripens. Late season is a time to conserve energy, not to start feeding again.

Common mistakes

• Leaving fruit out under frost.
• Feeding and heavy watering at the end of the season.

October — End of season

This month

What to do

• When plants are finished, remove them whole, with stakes and ties. Do not leave them in the garden.
• Don't put diseased plants into ordinary compost: some diseases overwinter in the debris. If unsure, dispose of them away from the garden. Healthy plant material can be composted.
• Clear the wild nightshade-family weeds around the garden as well.
• Note where the tomatoes grew — move them to a new spot next year.
• Wash and put away stakes and cages.

Why

Some disease-causing organisms — for example early blight — overwinter on diseased plants and weeds. A clean garden in autumn lowers the pressure next year.

Common mistakes

• Composting diseased plants.
• Leaving plant debris "for winter".

November — Soil over winter

What to do

• Add compost or well-rotted manure to the soil if needed, using only healthy material.
• Where you can, sow a cover crop (green manure) for winter.
• If you haven't done a soil test in years, now is a good time — results show what is actually missing.
• Put tools and containers away cleaned.

Why

The soil rests over winter, but decisions made now — organic matter, a cover crop, a test — carry into the whole next season.

Common mistakes

• Leaving bare soil all winter.
• Fertilizing without knowing what's missing.

December — Rest and review

What to do

• Go over your season notes: which variety did well, what problems appeared, how much and when you watered.
• Draw up a plan for next year — new beds, varieties, timings.
• Check your seed stock and store it somewhere cool and dry.
• Read the guides for the problems that gave you trouble this season, so you know what to watch for.

Why

The best calendar is your own: it shows what really works in your garden and your climate. December is when it is easiest to put together.

Common mistakes

• Starting the new season without notes from the last one.