Tuesday, August 02, 2016

Sowing and Nutrition - for Seed Sown Zoysia

This question is a perennial one that is regularly asked by those developing a new turf area.  While there are some guides about how to sow seed, the nutrition aspects are not widely available particularly for conditions outside of the USA.  

Zoysia from seed is effectively established with modest nutrition – we suggest 2 applications each of 200g / 100 sq m of a good mixed NPK fertiliser with trace elements, applied evenly to dry soil before sowing and raked into the soil, and at 3-4 weeks after sowing which can be irrigated into the ground.  Suitable products include Yara Hydrocomplex NPK 12:15:10 [or similar as many blends are close to this] plus trace elements and iron.  Others potentially available include Crop King 55 and 88, Nitrophoska Blue and a range of other suitable all-purpose fertilisers used at sowing depending on availability at your local supplier.

Follow that by switching to a slow release fertiliser eg Scotts  - [ or other brands that may be available from many garden shops incl Bunnings and BigW in 2kg and 4 kg  bags, but do not use any with herbicide while the area is so young], applied at about 6-8 weeks  from sowing and thereafter at 12 week intervals in year 1 – you can use about one half of the recommended rate for zoysia – the recommended rate is broadly based for use on couch.  After that maybe 2-3 times a year is enough -August to October [depending on location], early March and [maybe in warm areas] May. for larger areas, sometimes a 25kg bag is a sensible buy - store it in a secure lidded plastic pail and it will be okay for several years. 

Slow release fertiliser is strongly recommended for all zoysia turf areas.  Avoid excess fertilising and non-slow release nitrogen fertiliser – that encourages thatch development.

If more green colour is needed for your turf – apply 0.5% - 1% iron sulfate solution [no stronger please] – great colour can be achieved but not too much growth! 

We strongly suggest additional potassium in September/October and March each year [ southern hemisphere areas] – use potassium sulfate [sulfate of potash] at 1kg / 100 sq m, and avoid muriate of potash.  This potash product is sold in 1.5 and 2.5 kg pails from many major garden stores and also is available in larger sizes [25kg] if required.

At sowing, a very light mulch cover can be helpful to manage and assist with holding moisture close to the surface during the vital early few weeks.  Light materials are best including sugar cane mulch and mature fine compost or similar, with a very thin cover helpful – no more than 1-2mm that holds moisture close to the surface where the seed is germinating.  

After sowing, irrigation during the day, for a few minutes each time, is needed to dampen the surface but not make it too wet.  As to the number needed - suggest 2-3 times each day at late morning and early afternoon as a start………but need to adjust as needed, and it will be temperature and wind dependent.  This can be reduced once seedlings emerge – some individual judgment is needed on this issue, as all sites and conditions are different.  The need is for SURFACE DAMP not SURFACE  DROWNING.

Seed emergence can be sped up with seed priming – soak seed for up to 36 -48hrs in warm [definitely not cold] water at around 20C eg and keep inside where it is warmer, then drain and lay out seed to surface dry in the sun next morning………..can speed emergence by a quite a few days [ see info from Pickseed].

Weeds can be troublesome at some, often older or renovated sites.  Make sure the weed is identified correctly before rushing to use any herbicide. Often repeated mowing will aid removal of the weeds as the turf species develops and strengthens often choking out the weeds. 

DO NOT use glyphosate / Roundup® or similar products on zoysia – it is quite sensitive to this type of product!  There are some products that may be useful; with an MCPA /dicamba mix often well suited for broadleaf weed control [one trade name is Kamba M – there are some others].  Try to avoid use of herbicides when the area is very young, unless you really understand what you are doing or have sought professional advice.  If in doubt ask us – there are often solutions available.

Prepare in advance, be organised at sowing and be prepared to invest time and effort then – it will be rewarded with a great lawn nearly always achievable [If in doubt, checkout the You Tube videos].  Most poor outcomes are traced back to problems at sowing and site preparation.

For larger zoysia seeded areas – eg over 1000 – 2000 sq m, often using hydroseeding may be a suitable option.  It works very well with the mulch used at sowing acting as a very good surface mulch and erosion management tool.  For smaller areas costs of cleaning equipment before hand  can make using hydroseeding too expensive, even though results are generally very good.

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