Monday, August 15, 2016

Sowing Seed of Zoysia Turf - The Weather!

Timeliness is critical in many parts of the Australian mainland for successful sowing of zoysia seed for a turf area.

Not too hot, and not too cold is a good theme.

In northern areas above the Tropic of Capricorn, it is,  in a broad sense okay to sow most times of the year, except for cooler highland areas and inland where nights can be awfully cold in those winter months........avoid them!  We also caution about sowing in most years after April [last year was an exception as it was still very hot at that time] as with cooling and shortening days, while germination and establishment will be okay, it is almost impossible to easily develop a lawn due to cooler conditions with development often delayed until the weather warms after August.

As a best practice guide, sow from early to mid August onwards, when days are warm [above 25C] and nights around 18 -20C, or more.

The amount and quality of light is also important, with the much shorter days prior to August also slowing plant development, even slowing germination as zoysia is very light sensitive at germination.  As days lengthen noticeably from August it provides a boost to young zoysia growth, especially in combination with the arrival of warmer weather.

By October, storm rains are approaching and erosion can be an incredibly tricky issue on a bare site just ready for sowing, so some erosion management on the site is often needed, with a light soil mulch cover often a possible solution. However, it is warmer and germination is often a little quicker.

Ideally, a balance between August through September is mostly the best time to sow, striking a balance between warm enough but also when irrigation to establish the area is most effective and the weather is not so hot that applying water to a new area is often a problem.  It can be that there may even be water restrictions late in the dry season in some locations.

With suitable site management plans in place sowing through to December is certainly feasible, especially using hydroseeding that offers surface protection from the mulch placed on site with the seed.  Avoiding monsoonal weather months is sensible, unless there are very pressing needs, eg experienced landscape professionals.  Even then, more care is needed, and often inter monsoon periods may offer opportunities to get the planting done with less chance of failure.

Elsewhere around Australia in more temperate and sub tropical areas, later sowing is more sensible with September and October more likely to be the appropriate early sowing months.  Avoid late summer [March] and into autumn - there may not be enough time to fully develop the lawn before the cold weather arrives.  Remember that all sites do vary, even with some local minor quirks.

Help is available though,  to allow some strategic planning.........the BOM has excellent long term records for climate statistics for almost everywhere around Australia.  Get online and check your area.

You need daily average maxima to be near or above 20C and minima to be in the 10 - 15C range or more.  If your area is outside this range..........wait until it warms up more.  A prudent two week wait for warmer weather can pay off! 

While these are averages suitable for planning, daily records are also available for the past 24 months, giving a more accurate near term idea of temperature and rainfall trends.

If the weather is still cold........WAIT.  Zoysia is cold tolerant once established, but small young seedlings can be affected by cold weather.

Seed priming may help speed germination.  Read about it in a recent blog post.

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