Days to Maturity Calculator
Calculate estimated harvest date from planting date and crop days-to-maturity. Enter values for instant results with step-by-step formulas.
Formula
Harvest Date = Planting Date + Days to Maturity (adjusted for growing method)
Days to maturity is the number of days from planting (or transplanting) until harvest readiness. Growing method adjustments: greenhouse reduces DTM by 15%, indoor by 10%, raised beds by 5%. A 10% window on either side provides early and late harvest estimates.
Worked Examples
Example 1: Spring Tomato Planting
Problem: Tomato transplants are set in the garden on May 1. The variety has a DTM of 75 days. When is the expected harvest?
Solution: Planting date: May 1\nDays to maturity: 75 days (from transplant)\nHarvest date: May 1 + 75 days = July 15\nEarly harvest window: May 1 + 68 days = July 8\nLate harvest window: May 1 + 83 days = July 23\nGrowth stages: Flowering around June 10, fruiting by late June
Result: Harvest: July 15 | Window: July 8–23 | 75 days from transplant
Example 2: Greenhouse Lettuce
Problem: Lettuce seeds are started in a greenhouse on March 15 with a DTM of 45 days.
Solution: Planting date: March 15\nBase DTM: 45 days\nGreenhouse adjustment: -15% = 38 days\nHarvest date: March 15 + 38 days = April 22\nSuccession planting: March 29, April 12\nGreenhouse provides consistent warmth for faster growth
Result: Harvest: April 22 | Adjusted DTM: 38 days | Greenhouse -15%
Frequently Asked Questions
What does days to maturity mean for crops?
Days to maturity (DTM) is the expected number of days from planting until a crop is ready for harvest. For direct-seeded crops like beans, carrots, and corn, DTM counts from the day seeds are sown in the ground. For transplanted crops like tomatoes and peppers, DTM typically counts from the date the transplant is set in the garden, not from when the seed was originally started indoors. This distinction is important because starting tomatoes from seed indoors adds 6 to 8 weeks to the total growing time. DTM is an estimate that varies based on growing conditions including temperature, sunlight, soil quality, water, and variety. Seed packets and catalogs list DTM as a guide, but actual harvest timing may differ by 10 to 20 percent depending on local conditions.
How do growing conditions affect days to maturity?
Growing conditions significantly impact how quickly crops reach maturity. Temperature is the primary factor — most vegetables have optimal growing temperature ranges, and growth slows outside these ranges. Warm-season crops like tomatoes grow fastest between 70 and 85 degrees Fahrenheit, while cool-season crops like lettuce prefer 60 to 70 degrees. Greenhouse growing can reduce DTM by 10 to 15 percent due to consistent temperature and protection from wind. Raised beds warm up faster in spring, potentially reducing DTM by 5 percent. Adequate water and proper fertilization support optimal growth rates, while drought stress or nutrient deficiencies extend the time to harvest. Light levels also matter — plants receiving full sun (6 or more hours daily) mature faster than those in partial shade. Altitude and latitude affect growing seasons through temperature and day length.
What crops have the shortest and longest days to maturity?
The fastest-maturing garden crops include radishes at 22 to 30 days, microgreens at 7 to 14 days, baby lettuce at 30 to 40 days, spinach at 35 to 45 days, and green onions at 30 to 40 days. These are ideal for succession planting and short growing seasons. Medium-maturity crops include bush beans at 50 to 60 days, cucumbers at 55 to 65 days, and summer squash at 45 to 55 days. The longest-maturing common garden crops include garlic at 240 or more days (planted in fall, harvested in summer), onions from seed at 100 to 120 days, winter squash at 90 to 110 days, watermelons at 80 to 100 days, and Brussels sprouts at 90 to 110 days. Fruit trees and perennial crops take years to reach first harvest, with apple trees typically taking 3 to 5 years from planting.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
How do I get the most accurate result?
Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.