The Basil in The Leaf Spa

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It is time to reflect on what/how the basil is growing. What should I change to increase the plant’s quality given the Leaf Spa’s environment?  What should I change to the basil plants and/or environment to be more pleasing and better aligned to our family’s use?  Should I explore other varieties?

Based on explorations I did for this post:

  • I am happy with the current temperature.
  • I am changing the photoperiod to be 20 hours on and 4 hours off. This will achieve a higher DLI.  
  • I am evolving my use of basil.  
  • I will stay with the two varieties I am currently growing.


Two varieties are currently grown in the Leaf Spa, genovese and sweet basil.  While I am attempting to clone, I am also buying new seeds to begin at the beginning on a more focused approach to studying the basil growth, taste and use.

For now I’m going to stick to these two.  


I ran the script on several days worth of log data:

Seconds between readings: 60        
Target CO2 level: 1200        
Seconds for warmup: 180        
Seconds pump is on: 60        
Seconds between turning pump on: 1800        
Hour lights turn off: 12:00 AM        
Hour lights turn on: 8:00 AM        
–Average Values–          
LED ON     LED OFF    
Temp Humidity CO2 Temp Humidity CO2
23.9/75 72.9 1127 20/68 71.2 484

Measurements are grouped into whether the LEDs were on or OFF.  


  • The photoperiod is 16 hours, with lights off between 12AM and 8AM.
  • The pump circulates the nutrient bath every 30 minutes for 1 minute.
  • The target CO2 level when the lights are on is 1200ppm.
  • Readings are taken every minute.


I have been generalizing without much background that the “best” temperature for basil ranges between 70˚F and 85˚F.  This is based on information I got from the article titled Managing Air Temperatures For Basil Growth And Development.  Given the advice in this article, the Leaf Spa temperature readings are spot on.  I am thrilled these temperatures occur without the system having to control heat/air conditioning.  But is the pain/cost involved with adding an HVAC system at this point worth the gain in growing even better basil?  I’m happy with current results…but….but…

Could (should) they be better?  I googled to see if there has been research on the ideal temperature for growing basil (or herbs) within a controlled environment and came up with the article The Effect of Air Temperature on Growth of Eight Herb Species.  Author Leiv M. Mortensen comes from the perspective of how herbs are currently grown in Norway:  Relatively low temperatures of 13t o 18˚C have been recommended for herbs [1] [2], and temperatures below 20˚C are used in the greenhouse production of herbs in Norway

Based on Mr. Mortensen’s tests that are described within the article:


 He notes:  A substantial increase in the fresh weights of all eight herbs (ranging from 40 to 126%) was found to correspond to an increase in temperature from 18˚C to 24˚C or 27˚C.  Mr. Mortensen also posted a table on the plant’s height relative to the temperature.

Focusing on the basil results:

Basil     Temperature      
  18 21 24 27 27/15 24/18
weight (g) 52 63 85 107 82 68
% increase between   21.15% 34.92% 25.88%    
% increase from 18     63.46% 105.77%    
height (cm) 8 9 14 18 13 10
% increase between   12.50% 55.56% 28.57%    
% increase from 18     75.00% 125.00%    

I looked at the % increase in weight and height between the temperatures and between 18˚C and 27˚C.  Assuming these temperatures for 24 hours, the 27˚C temperature hows the 106% increase in weight and 125% increase in height.  Lowering the temperature for 12 hours to 15˚ or 18˚C acts more as an average.

I’d like to keep the plants shorter.  From the results, the higher the temperature has a significant affect on height.  Yet, the higher temperature as an equally significant affect on the size and number of leaves.

Given the temperatures I am currently seeing – 24˚C for 16 hours and 20˚C for 8 hours, I do not see a need for additional heating at this time.

However, I think of tweaking the Leaf Spa elements – like DLI – as the way I might adjust the amount of salt in a cooking recipe. In this case, I’m going to increase the LEDs being on by 2 hours.  So now the photoperiod will be 20 hours and 4 hours off. 

Frustrated Geez – I updated to Arduino IDE 1.8.2.  The problem with this is now the executable is Arduino  This executable has the version of the SD library that does not include end().  Perhaps “the right “ the to do is figure out a method to evolve to using the SD library so I’m not fumbling with the Arduino executable.  For now, I’m going to do what I did in this post.


I’d like to thank the basil plants for donating leaves so that I could make pesto for my family:

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I have a fairly standard lunch routine in which I enjoy a magnificent salad.  Another big THANK YOU to the basil for donating daily leaves.  

Other Uses

I want to expand my use of a plant as I get to know it better.  I have seen basil ice cream and other culinary creations for basil.  Seems basil is quite the party pleaser, making almost any dish taste better.

Essential Oil

I’ve been thinking of ways to get the incredible smells I enjoy whenever I get a whiff of the basils.  It is time I DIY’d my own essential oil.  Here are the recipes I will be following that are on the Superbherbs archived site:

Cold Method
1. Let the herb you want to infuse sit overnight, so it will lose water. 
2. Fill a jar with as much herb as you want to infuse to 3″ from the top. 
3. Fill the jar with oil enough to cover the herb, plus 2″. Because herb exposed to air will mold, make sure all the herb is covered. 
4. Let sit in the sun or in a greenhouse for six to eight weeks. 
5. Strain into a clean, airtight, dark jar. Label, date, and store in a cool, dark place. Don’t be surprised if the oil doesn’t smell like the plant. It most often doesn’t. For a stronger oil, repeat the process. Double oleate oils are twice as strong, and triple oleate, three times as strong, etc.

Hot Method 
1. Let the herb you want to infuse sit overnight, so it will lose water. 
2. Fill a pot with as much herb as you want to infuse. Use a non-reactive pot. Glass is my first choice. You also can use stainless steel, enamel, or cast iron. Do not use aluminum or copper. 
3. Cover the herb with oil and add two more inches of oil. 
4. A double boiler is convenient, but if you don’t have one, put the pot in a bigger pot that has water in it. The oil should heat slowly over low heat for three hours. Do not overheat because too intense heat will destroy the volatile oils you are trying to collect. You can do this in a crockpot on the lowest setting also.
5. Strain into a clean, airtight jar, and store in a cool, dark place.

I’ll start by trying the hot method.    I saw this 16 ounce crock pot on  Since I had A LOT of orange peels around (my sister regularly sends me fruit from her garden 🙂 ), I’ll try the hot method first with orange peels.


I hope all is well with you.  Please find many things to smile about.