Five fixed example schedules, not cultivar predictions: lettuce 32, basil 40, tomato 70, strawberry 100, pepper 80 days from sowing. Adjust for your seed supplier and growing conditions.
Timing is everything in a productive hydroponic garden. If you want a continuous harvest of lettuce or a perfectly timed crop of peppers, you need to work backward from your goal.
Our Germination Calendar helps you map out every milestone from the first drop of water to the final harvest.
Quick answer
Five fixed example schedules, not cultivar predictions: lettuce 32, basil 40, tomato 70, strawberry 100, pepper 80 days from sowing. Adjust for your seed supplier and growing conditions. The broader reference table below is not the widget’s data source; microgreens, kale and beefsteak tomato are not selectable.
How to Use This Calculator
Five fixed example schedules, not cultivar predictions: lettuce 32, basil 40, tomato 70, strawberry 100, pepper 80 days from sowing. Adjust for your seed supplier and growing conditions. Select one of those five crops and a harvest date to subtract the example duration. Sprout/transplant offsets are also fixed examples, not observations.
The Three Phases of Early Growth
1. Germination (The Sprout)
The time it takes for the seed to crack and the first "cotyledon" leaves to appear.
- Tip: Keep it dark and warm. Light isn't needed until the sprout breaks the surface.
2. Seedling Phase (The Nursery)
The time between sprouting and being "system-ready."
- Tip: This is when you start "light" nutrients (1/4 strength) and move the plants under grow lights.
3. Vegetative / Flowering (The Main System)
Once transplanted into your DWC, NFT, or Dutch Bucket system, the plant's growth accelerates.
- Tip: Use our System Sizer for a rough reservoir and budget example; assess mature crop spacing separately.
General crop reference (not calculator schedules)
| Crop | Days to Sprout | Days to Transplant | Total Days to Harvest |
|---|---|---|---|
| Basil | 5 – 10 | 14 – 21 | 45 – 60 |
| Lettuce | 2 – 5 | 10 – 14 | 35 – 50 |
| Kale | 3 – 7 | 14 – 21 | 50 – 65 |
| Tomato | 5 – 10 | 21 – 28 | 80 – 100+ |
| Beefsteak tomato | 5 – 10 | 21 – 28 | 100 – 140 |
| Mustard microgreen | 2 – 3 | n/a (no transplant) | 7 – 10 |
| Buckwheat microgreen | 2 – 3 | n/a (no transplant) | 10 – 14 |
| Beet microgreen | 3 | n/a (no transplant) | 12 – 18 |
| Radish microgreen | 2 – 3 | n/a (no transplant) | 7 – 12 |
Microgreens skip the "transplant" milestone entirely — they're harvested in-tray, so their calendar only has two stops: sow and cut.
Worked Example: Planning a Lettuce + Mustard Microgreen Combo
Say you want a salad-ready lettuce head and a batch of mustard microgreens ready on the same date, 40 days from now.
- Lettuce (manual 40-day plan, not the widget’s 32-day example): Sow today. Expect sprouting in 2–5 days, transplant to your system around day 10–14, harvest around day 35–50. A 40-day target sits comfortably inside that window.
- Mustard microgreens: Because mustard finishes in just 7–10 days total, sowing today would leave the tray idle for a month. Instead, sow mustard around day 30–33 so it's ready to cut right as the lettuce reaches harvest size.
This is the core value of working backward from a target date — fast crops get sown late, slow crops get sown early, and everything lands on the same table at once.
Common Mistakes When Timing a Grow
- Counting "days to harvest" from transplant instead of seed. Most published crop data (including the table above) is seed-to-harvest. Sowing on your intended transplant date pushes your actual harvest back by however long germination and the seedling phase take.
- Ignoring media temperature. Cold media (below 18 °C) can double germination time for warm-season crops like tomato and pepper — plan an extra 3–5 days if you're not using a heat mat.
- Sowing all seeds for a crop on one day. This creates feast-or-famine harvests. Stagger sowing (see below) instead.
- Skipping the dark/blackout phase for microgreens. Brassicas like mustard and beet germinate faster and more evenly under 2–3 days of blackout before light exposure; skipping it produces uneven, leggy shoots.
- Not accounting for slower fruiting crops in shared grow space. A beefsteak tomato occupies its spot for 100–140 days — nearly 3× a basil cycle — so shared-tent planning needs to weight it accordingly.
Pro Tip: Stagger Your Sowing
Don't plant 20 lettuce seeds on the same day unless you want to eat 20 heads of lettuce in the same week. Plant 5 seeds every 10 days for a "perpetual harvest" that never leaves your fridge empty or overstuffed. The same logic applies to fast microgreens — sowing a quarter-tray every 2–3 days keeps a steady supply of mustard or radish microgreens without a harvest glut.
See Also
- Hydroponics for Beginners — Getting started with your first seeds.
- Lighting for Seedlings — How much light do babies need?
- Crop Planner — A more advanced tool for multi-week grow schedules.
- Mustard microgreens — Fast 7–10 day cycle detail.
- Beefsteak tomato — Longest common hydroponic cycle detail.
FAQ
How long does lettuce take from seed to harvest?
In a hydroponic system, most loose-leaf lettuce takes 35–45 days. Head lettuce can take 50–60 days.
When should I transplant seedlings into my system?
Usually when the first "true leaves" appear and roots are visible outside the starter cube (about 7–14 days).
Can I speed up germination?
Yes. Using a heat mat to keep the media at 75°F (24°C) and keeping humidity high with a dome can cut germination time in half.