I’m making great progress with the grass. I can not add it to the map on any surface, and it grows daily, each grass tile having it’s own growth.

My previous number of max 2 mm per day was a bit low, specially when I considered it to be the max at max insolation. So I gave it 50% growth (1mm/day)at 50% insolation (4), and that resulted in 10 mm growth from start of year until april, and reaching 20mm at late july. That seemed to low considering having been informed that it can grow in 10 days during summer, so I made more searches regarding the topic, and got this:

The rate of grass growth depends on the type of grass, weather, amount of sun, water and other factors. Generally, grass grows at a rate of 2 to 6 inches a month, or an average of .06 to .20 inches a day. (source)

That means 0.1524 to 0.508 centimeters.

That’s more that twice my max. And then this:

It depends on:

  • the time of year (affects height of Sun)
  • the amount of shade
  • whether there has been recent rainfall
  • recent temperatures
  • the condition of the soil
  • the species of grass
  • the use of fertilizer

In subtropical and temperate climates where there is significant seasonal variation in temperature and sunshine, growth can completely stop in Winter.

In late Spring, Summer and early Autumn (Fall) grass will grow as much as conditions permit with the height of Summer representing the peak of solar radiation and therefore the greatest potential for growth as long as moisture is available.

Recently in Sydney, the first month of Summer coincided with significant rains and very warm, humid days. All of the Summer grass species that are common in the Southern Hemisphere grew at an absolute maximum rate irrespective of fertilizer. I estimate growth was (and still is) occurring at about 1cm (3/8″) per day. I estimate this is 1.25X the normal Summer growth in Sydney. (source)

Wow, a full cm per day!

That’s 10 times my maximum! I’ll put that as the new maximum under optimal conditions, maybe even more, since I guess those were only 80% of truly optimal conditions, considering he specifically mentioned “irrespective of fertilizers.” So 12 mm/day is the new maximum.

Now, I just need to add more parameters to make it sub-optimal, and he mentioned a few at the top.

I’ll add a video later.

EDIT: Water needs:


many gardeners in the south do sow in winter, but ideally the ground temperature should be 6C at least. Our fridges are usually set for 5C for a good reason – at this temperature not a lot happens in terms of mould or any other type of growth. Although Guy did mention they do sell a grass seed ‘Anytime’, which was launched recently, composed of three types of rye, which will germinate at 2-3C.

James Grundy of Pitchcare points out that the two main factors for germination are temperature and moisture. Often soil temperatures on the surface can warm up remarkably quickly with a bit of sunshine. A soil thermometer is an extremely handy bit of kit and the results can often surprise you (a great guide to sowing early veg, too).

Bald areas in your lawns can creep in from too much shade as trees expand their canopies. If you don’t want to increase the light by reducing the canopies, maybe you should forget grass in these areas altogether. In one such area, my orchard, I have planted low sheets of Symphytum ‘Hidcote Blue’.





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