Comparison

Mars Legacy vs VPD Chart

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Mars Legacy

Control and configure your indoor grow lights remotely. Automate growth cycles with custom timers, simulate sunrise and sunset, and manage multiple lights independently from a single device. Compatible with the Mars Hydro Smart Grow System.

Highlights
  • Remote LED light control
  • Adjustable light intensity
  • Automatic growth cycle programming
  • Sunrise/sunset simulation
  • Wireless multi-light control
  • Independent lighting group management
Read full description

The Mars Hydro app is launched to build a smart, simplified, frontier a ccess for growers to a more manageable grow project, supporting m obile control and growth programs configuration, compatible with Ma rs Hydro Smart Grow System at: www.mars-hydro.com *Easily turn ON/OFF your LED grow lights and adjust the intensity with j ust a few clicks. *Precisely arrange time triggers to achieve automatic growth cycles an d simulation of sunrise and sunset. *Wireless control of multiple LED grow lights via one device at the sam e time. *Different lighting groups are available for independent management, which enables simultaneous monitor on paralleled grows. ...More to be launched

About

VPD Chart

This app calculates Vapor Pressure Deficit (VPD) using air temperature, relative humidity, and canopy temperature. It offers real-time charting, sensor integration, and educational tools to understand plant growth environments. Organize data by zones and visualize dew point areas.

Highlights
  • VPD calculation
  • Interactive VPD chart
  • Sensor integration
  • Zone organization
  • Dew point visualization
  • Grow Timeline
Features
Read full description

The app calculates VPD using air temperature, relative humidity, and canopy temperature. View real-time VPD values on an interactive chart. Connect sensors for automated readings or manually input data via intuitive sliders and text inputs. Key features: • Interactive VPD chart with manual input • Default crop types • Organize charts by assigning them to different zones • Display spots that share the same VPD value • Zoom in and out of the VPD chart with a two-finger pinch and drag to pan around • VPD Target - long-press the chart to set a target VPD value • Dew point area visualization • Grow Timeline • Sync sensor historical data by importing it from sensor's app, via cloud APIs, or bluetooth • Explore sensor history by panning and zooming Supported bluetooth devices: • AC Infinity Cloudcom B2, A2, B1 • SensorPush: HT1, HT.w, HT.xw • Govee: H5051, H5072, H5074, H5075, H5100, H5101, H5102, H5103, H5104, H5105, H5174, H5177, H5179 • SwitchBot: Meter, Plus, Indoor Outdoor • Ruuvi: RuuviTag and RuuviTag Pro • Inkbird: IBS-TH1, IBS-TH1 Plus, IBS-TH2, IBS-TH2 Plus • ThermoPro: TP351, TP357, TP358, TP359 • VIVOSUN AeroLab THB1S • Shelly BLU H&T • Xiaomi Mijia 2 (LYWSD03MMC) (original and pvvx firmware) Supported devices with API connectivity: • Govee • Pulse • UbiBot • Ecowitt • Tuya • SensorPush Educational benefits: • Interactive Learning: Explore the dynamics of VPD based on changes in temperature and relative humidity by manipulating input sliders and animating the chart • Canopy - Air Temperature Link: Easily visualize and set values by linking canopy temperature to air temperature • Chart Bands Control: Toggle chart bands on/off (dew, under transpiration, prop, veg, flower, over transpiration) for a comprehensive understanding Included: 1 chart with manual input and grow timeline, device data sync & explore, default crops VPD Chart Plus subscription unlocks: • Unlimited charts • Automated VPD calculation by using sensors as the input data source • Background monitoring and Alerts (temperature, RH, VPD) • VPD history timeline, available on sensor-driven VPD charts • Custom crops Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Mars Legacy4 screens
VPD Chart4 screens

Verdict

The call

The clearest difference is review sentiment: VPD Chart at 74% against Mars Legacy's 12%. VPD Chart also leads on rating (4.5 vs 1.3). Mars Legacy's advantage is in-app purchases (none vs 2) and iOS requirement (13.0 vs 15.1). On price, ratings volume, update cadence and ads there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. VPD Chart sells 2 in-app purchases, starting at $3.99 per month. Mars Legacy asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

VPD Chart holds the better App Store score, 4.5 against 1.3. Both are backed by a comparable volume of ratings — 70 and 30 respectively. Written reviews point the same way: 12% of Mars Legacy's written reviews are positive against 74% of VPD Chart's.

UpkeepUpdate frequency

Mars Legacy ships an update monthly, VPD Chart every 3 weeks. The most recent releases landed on August 7, 2026 and September 22, 2026 respectively.

Scorecard5 real differences · 5 level
Mars Legacy versus VPD Chart: the parameters behind the verdict, then further details
ParameterMars LegacyVPD Chart
PriceFreeFree
Rating1.3 (70 ratings)4.5 (30 ratings) — better
Positive reviews12.2% of reviews73.7% of reviews — better
Number of ratings70 — better30
Update frequencyMonthlyEvery 3 weeks — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPodiPhone, iPad, iPod — better
Requires iOS13.0 — better15.1
Further details — not scored
Size59 MB49 MB
Age rating4+4+
DeveloperMARS TRADING RCC, INC.INNOVO DEV S.R.L.

Customer experience

Mars Legacy

All ratings70 ratings
Positive7.1%
Neutral0.0%
Negative92.9%
Written reviews90 reviews
Positive12.2%
Neutral4.4%
Negative83.3%

VPD Chart

All ratings30 ratings
Positive86.7%
Neutral3.3%
Negative10.0%
Written reviews19 reviews
Positive73.7%
Neutral0.0%
Negative26.3%

Bugs and requests

Mars Legacy

Reported bugs

20 issues
  • App cannot detect Bluetooth despite phone detecting it
  • Timer settings do not execute at scheduled times
  • Scenes and automation groups fail to work
  • WiFi connection drops frequently and reconnection fails
  • Light brightness changes unexpectedly without user input
Show 15 more
  • Humidity readings display unrealistic fantasy values
  • App crashes and loses all device/account data
  • Login verification codes not received
  • Sunrise/sunset mode ignores brightness settings and forces 100%
  • Time selection interface is confusing and unreliable
  • Fan disconnects from app during use
  • PPFD settings reset unexpectedly
  • App update broke existing functionality
  • Device not detected during initial setup
  • Password signup validation error
  • Bluetooth icon shows as disabled after update
  • Light turns off mid-cycle without reason
  • Temperature unit cannot be changed to Celsius
  • Scenes override manual timer settings
  • App fails to save time settings correctly

Requested features

12 requests
  • Multiple on/off cycles per day for automation
  • Daylight saving time adjustment option
  • Sunrise/sunset mode with adjustable brightness levels
  • Better WiFi stability and range
  • Improved app interface and user experience
Show 7 more
  • Comprehensive help documentation
  • Account recovery and data persistence
  • Multi-language support with accurate translations
  • System time picker instead of custom control
  • Ability to set different brightness levels for different scenes
  • More reliable remote control functionality
  • Better error messages and troubleshooting guidance

VPD Chart

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Mars Legacy

No in-app purchases

2 purchases

VPD Chart

Subscriptions2
  • VPD Chart Plus (monthly)3 Days trial$3.991 Month
  • VPD Chart Plus (annual)3 Days trial$29.991 Year

Questions

Is Mars Legacy free?
Mars Legacy is free to download, with no in-app purchases.
Is VPD Chart free?
VPD Chart is free to download, with in-app purchases available.
Which has better reviews, Mars Legacy or VPD Chart?
VPD Chart is rated higher. Mars Legacy averages 1.3 out of 5 from 70 ratings, while VPD Chart averages 4.5 from 30 ratings.
Do Mars Legacy or VPD Chart have ads?
Neither Mars Legacy nor VPD Chart shows ads.
Which is updated more often, Mars Legacy or VPD Chart?
Mars Legacy ships an update monthly, and VPD Chart every 3 weeks. Most recently, Mars Legacy was updated on August 7, 2026 and VPD Chart on September 22, 2026.

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