Hard Wearing Grass; High Quality Lawn Lawn UK is known for top quality premium lawn seed. This then initiates the seed to respond to a period of chilling. Before sowing i carried out lawn aeration, and scarification. Before mowing, remove the front roller on cylinder mowers to prevent flattening the grass. and August to October but again is changeable with weather. the species in the grass seed mixture that you choose, but it is Temperature and seed germination Symp Soc Exp Biol. Seed can be stored until conditions are ideal, whereas turves may deteriorate if they are not laid within 24 hours of delivery. Seed germinates most readily in early autumn and mid-spring. Divide large areas into small sections, or small plots into square metres or square yards. LJN's Business Objectives Group (BOG) is for any Pro serious about building their business. Consider sowing grass seeds when the temperatures are reaching 8-10 degrees and have consistency for two weeks. If the temperatures are outside of this range, the seed may not germinate or will take longer to germinate. This will help prepare the soil and give your grass the best chance of growing. 222879/SC038262. Likewise, in the fall, the air temperature may drop below freezing, but the soil might still be relatively warm. Close . The Importance of Temperature in Grass Seed Germination. The grass won't germinate until the following spring when soil temperatures warm. Eliminate perennial weeds such as couch grass or bindweed well before beginning to prepare the seed bed. However, you must note that different types of grasses require different conditions for them to germinate. The ideal time for this is March to May Getting grass seed to grow entails time, patience and above all, the proper conditions for seed germination. Join the RHS today and support our charitable work, Keep track of your plants with reminders & care tips – all to help you grow successfully, For the latest on RHS Shows in 2020 and 2021, read more, RHS members get free access to RHS Gardens, Free entry to RHS members at selected times », Reduced prices on RHS Garden courses and workshops, Our Garden Centres and online shops are packed with unique and thoughtful gifts and decorations to make your Christmas sparkle, General enquiries Soil and air temperatures both need to be considered. This is usually from March through until September. For many plants, the minimum germination time was found to be 50F (10C). Often you will find a monthly guide on a seed pack indicating when to sow seeds and this generally works okay, but can be misleading. You can also provide a fan to increase airflow in the grow room or greenhouse. Luxury or fine lawn: This is a mix of fine-leaved turfgrasses. This combination of warm soil, moderate day temperatures and cool evenings encourages fast germination and establishment of newly sown cool-season grass seed. With spring-sown lawns this means not until the following spring as their effectiveness diminishes rapidly with the onset of cooler conditions in early autumn. Odabaş and Mut (2007) reported 94 and 92% of the variation in rye and oat germination, respectively, can be explained by temperature. Grass seed requires sunshine, temperature, and water as the primary essentials for their ability to germinate. Many lawns can continue to look green and lush well into autumn and early winter. The farther north you live, the earlier cool fall temperatures and ideal planting time come. This is regulated by soil temperature according to the variety of grass. However, you can provide a loose growing medium that allows air to move around the seed. Grass seed requires soil, water, warm temperatures and nutrients in order to germinate. As the soil temperature rises you’ll see the grass seeds start to germinate and grow at a fairly quick rate. Seeding is less expensive than turfing. Just remember grass seed germination relies on two main factors – soil temperature, and moisture. This is no different in case of ryegrass. Cool Season Grasses Germinate Best Between 50 and 65 Degrees Fahrenheit. Seeds with intact seed coats that had not germinated were stained with triphenyl tetrazolium chloride to verify that they were dead and not dormant (Moore 1973). Air temperature and soil to seed are a few factors that determine germination rates. The following is a guideline for the accepted germination of individual species: Perennial ryegrass - 7 - 15 days with soil temperature range of 7 - 28°C Red fescue - 10 - 21 days with soil temperature range of 10 - … For the researching visitor there's a wealth of landscaping ideas, garden design ideas, lawn advice tips and advice about garden maintenance. Browse the complete range here and buy online from Collier Turf Care securely and with confidence. This roughly corresponds to daytime air temperatures in the 60°F to 75°F range. Soil temperature – the ideal soil temperature for grass seed is around 9-13⁰C which in the UK is usually achieved from the beginning of March until the beginning of October, but this season can be extended or reduced dependent on weather. Apply and rake in 70g per sq m (2oz per sq yd) of general-purpose fertiliser. generally relatively low maintenance to establish. This process of pre-germination will take five to 30 days depending on the type of grass seed. The soil is warm, there is plenty of moisture and the weather is neither too cold nor too hot. It is a source of immense debate on how to achieve optimum establishment when sowing grass seed mixtures. Guy Jenkins, consumer manager at Johnsons Lawn Seed, says many gardeners in the south do sow in winter, but ideally the ground temperature should be … Cool season grasses need a minimum range of 45 to 65 degrees while the warm season grasses require a … Cool-season turf does well even when the temperatures are a bit low such as in fall, while warm-season grass needs higher temperatures. Grass seed is best sown from late summer to mid-autumn; there is less competition from weeds, and the soil is warm, and damp from rain. When we plant our grass seeds, anticipation sets in and have us on pins & needles. Other factors include contact, presence, and consistency of moisture plus the age and quality of the seed. These germination times are extremely important. Germination should take between seven and 10 days and seedlings will become established before the first severe frosts in late autumn, this is the preferred time as the roots establish better through the winter. ... Watch for germination once the soil temperature reaches about 50 degrees F. In general, seed mixtures cover these main areas: General-purpose lawn: This is often a mix of hard-wearing grasses, and is suitable for areas that receive a lot of wear and tear, perhaps from children or pets, or for areas of high traffic. Cool-season grass seed germinates best when soil temperatures are between 50°F and 65°F. A mistake often made regarding watering, is to wet the surface of the lawn frequently. What are the minimum temperature at which grass will germinate (the seed being sown onto newly lain loam)? Soil Temperature. Various grass species germinate at different temperatures, and this also equates to how long it will take the grass seed to fully grow. Light and Oxygen – it is important that grass seed is not This rarely occurs when air temperatures are below 60 degrees Fahrenheit (15.5 degrees Celsius), as the soil takes longer to … A germination test is required to establish whether Basic seed meets the germination standard and CS seed meets the minimum percentage germination set out in column 2 of the table. Shady lawn: These lawns will tolerate light to medium shade, such as under trees and next to fences or hedges. The optimum range for carrots is between 7 deg C and 29 deg C with far faster germination rates once the soil hits 10 deg C. Several factors will determine the germination rate of grass seed. Soil temperature, depth of planting and soil moisture are all key factors. times, RHS video: laying a lawn from seed or turf, RHS Registered Charity no. You should choose your lawn What is the ideal temperature for seed germination is a simple question but the answer is actually quite complicated. RHS video: laying a lawn from seed or turfSports Turf Research Institute, Join Perennial ryegrass and the advanced 4turf® Perennial ryegrass varieties For special conditions, Turf annual ryegrasses are an option – they will move on to leave space for traditional species. During September top-dress with sieved compost to fill in any irregularities. After cultivation leave for several days to settle - the longer the better, ideally five to six weeks or more. Repeat the process with the remaining seed, working in parallel rows widthways. These finest quality grass seed mixtures are designed to look perfect but still be versatile. Germination Temperature. A little care in the preparation of the ground when growing a lawn from seed can give superb results, more cheaply and easily than from turf. Temperature is one of the most important factors in grass-seed germination, but there are also other crucial elements to remember. The sun gets higher in the sky and the temperature starts to rise while the rains provide the moisture needed for germinated. Unfortunately cheap seed blends are often contaminated with weeds, or contain coarse agricultural perennial ryegrass, not turf ryegrass, meaning you'll get a lawn more suitable for grazing sheep than family barbeques. Or are they either warm-season or cool-season grass seeds? The germination process. Bear in mind that seed sown in the south of the UK will germinate sooner than that sown in the north of Scotland. Other factors include contact, presence, and consistency of moisture plus the age and quality of the seed. Cool-season grasses like Jonathan Green Black Beauty can be planted in cool temperatures. Either way, a fair range for grass seeds to germinate can be anything between 5 to 30 days. Seeds continuously deteriorate and, unless in the meanwhile they are … Germination Aid ranges available. As you now know, grass seed germination time depends on several factors. Make sure it is well-rotted, as un-rotted organic matter will cause the soil surface to sink unevenly as it decays. Ideally use a cylinder-bladed mower. Calculate the correct seed quantity for the area to be sown using the supplier’s recommendation or if unavailable: Birds can eat seeds and may disturb the seedbed by ‘dust-bathing’. Are they a mixture? How long will it take for the ro temperature requirements. What Temperature is Right for Laying Down Grass Seed? The environmental temperature matters a lot in grass seed germination. The Royal Horticultural Society is the UK’s leading gardening charity. You could also pre-germinate your grass seed prior to sowing it which will give it a head start. Dormant seeding can … There is no need to feed spring-sown grass in the first autumn. It goes without saying that you always get what you pay for, and the same goes for grass seed. I am often asked to repair small patches in lawns and thus usually use grass seed. dependent on weather. However, some will undoubtedly germinate in the new lawn. In early autumn, the soil is still warm from months of summer sun. Soil temperature affects the germination process as well. Different types of seeds germinate at various times, and it is important to take that into consideration when planting. If autumn-sown, try to avoid using it earlier than June and if spring-sown, use it as little as possible up to late autumn. Successful grass seed germination and establishment can sometimes be difficult. Pour grass seeds into the dustbin and mix with a long spoon until all of the seeds are thoroughly wet. Cool season grass needs soil temperatures between 45 to 55 degrees. Your order contains no items. “She’s lost the plot”, you might be thinking. 1988;42:109-32. Pay particular attention to clearing weeds and cultivating the surface to a fine tilth. want to achieve and the amount of time and effort you want to put in to GrassSeeds.com supply a wide range of grass seed for speedy delivery throughout the UK. Grass Seed. It needs to be spread on open soil and lightly raked to allow sufficient light and You have to plant the correct grass seed type based on the time of year and your location. The germination of your grass seed depends very much on Germination Temperature. If dry conditions persist, repeat watering as necessary while the seeds are germinating and the young seedlings are becoming established. The time period for grass seed germination varies on the grass seed type. The soil temperature needs to be between 9-12 degrees Celsius for seed to germinate. Many lawns can continue to look green and lush well into autumn and early winter. This helps seed germination and aids the grass in absorbing valuable nutrients from autumn fertilisation. If you have a long cold winter and the soil is cold, germination will be delayed and in some cases the seeds may rot in the ground. Weed seedlings are usually killed when mowing begins, but the seedlings of perennial weeds are best weeded out by hand using a hand trowel or fork. Use weedkiller, or hand weed. Once firmed, rake several times in different directions. In the autumn, the opposite is true. Sow half the seed over the whole area by working in parallel rows lengthways. This is no different in case of ryegrass. erning seed germination in moist soil (Dürr et al., 2015). The environmental temperature matters a lot in grass seed germination. This method of sowing grass is called dormant seeding. Temperature plays a huge part in how successful you will be at planting grass seed. It is necessary for the seeds and soil to connect for proper germination. Dig in some well-rotted manure or other organic matter (especially on a sandy soil) to hold moisture. In Conclusion. Also, remember that the soil in your area is probably a few degrees cooler than the air itself. That means that the soil is nice and warm, the seeds are kept moist, and the seeds are fresh. inc. VAT. Weather conditions and soil conditions are very crucial for seed germination and its faster growth. Before sowing i carried out lawn aeration, and scarification. You only need to look at the thread of comments and observations on the Pitchcare message board to see that it is something that concerns many turf managers who experience variable results. Different types of seeds germinate at various times, and it is important to take that into consideration when planting. In the absence of these try carefully treading raised areas. These are the necessary conditions for effective grass seed Some grass types, such as Kentucky bluegrass, germinate more slowly than others, such as ryegrass. Soil temperature should be at least 8 degrees Cº or for successful germination. hi there, i recently sowed some new grass seed on my very patchy back garden, this was carried out on the 31/03/2014. In theory soil temperatures no lower than 6 degrees centigrade grass seed will germinate. Inconsistency and frequent dropping of this temperature may cause more prolonged germination and establishment period. Curiously carrots’ ideal germination temperature is 27 deg C – I can’t imagine the soil in the UK hits that high often, if at all! The percentage germination from each bag of seeds was divided by the average percentage germination of the three controls to correct for any variables besides temperature. LJN's professional business forum is unrivalled and open to anyone within within the UK landscape industry. The resulting lawn will be very fine in appearance, slow growing and you'll be able to mow at a low height. seed lawn. There are many different seed mixtures available to gardeners, which can sometimes be confusing. Although the preferred time to sow grass seed is the late summer or early fall, you can successfully sow grass seed in the winter. Ensure the correct conditions when you seed your lawn for the best results. As the seed ages, the percentage of seeds that will be able to germinate diminishes, forcing you to use more seed than normal to get adequate coverage. On average, the UK usually has sufficient rainfall in March – April and September – October. Grass seed will germinate when soil temperatures reach a consistent 55 degrees and air temperatures reach 60 plus degrees. rainfall to germinate and grow well. All you can do to prevent this is by choosing a reputable brand, and reading the ingredients, making sure any perennial ryegrass included is 'turf' or 'fine' ryegrass. Generally, we recommend sowing grass seed in mid-late spring and … Dig or rotovate the site to a depth of 20-25cm (8-10in). Lay down the grass seed with a spreader and then rake over the soil and freshly laid seeds. Seeds also require adequate moisture to germinate and grow. The best way to determine your soil temperature is … We spoke in the previous post on how cool & warm season grasses react differently when it comes to the climate. Do not use residual weedkiller, as it can remain in the soil and will prevent the grass from germinating. seed is around 9-13⁰C which in the UK is usually achieved from the beginning of March The following guidelines will help you to achieve this. Understanding how fast does grass grow from seed also takes understanding the factors a seed needs to germinate. Some seeds have more than one barrier to germination that have to be overcome in a certain order. So shady lawns are usually not very hard-wearing. There are many other mixtures for sale promising 'quick' lawns, 'drought tolerant' lawns, 'easy' lawns and so on, but have a look at the ingredients, and they will usually be very close to those mentioned above. Sowing seed in spring, grass will want to flower quite early before roots have established. There are a number of ideal conditions for the best grass Next, simply fertilize the soil and keep the grass damp until the seedlings are least two inches tall. For example, premium shade, which is a fine quality lawn mixture also grows well in the shade. Temperature plays a huge part in how successful you will be at planting grass seed. Common seed mixtures such as perennial ryegrass and tall fescue take about 12 to 14 days to germinate. Our seeds are of exceptionally high quality, certified in line with DEFRA quality standards of purity and germination. Preparing your grass seed is the best way to ensure optimal germination and the fastest germination. O ver Christmas I was busy sowing grass seed. Seeds germination time varies from 4 days to as long as several months. If conditions are less than ideal, germination can take even longer than the expected times dictate. hi there, i recently sowed some new grass seed on my very patchy back garden, this was carried out on the 31/03/2014. However, always think about what you need from your lawn, in terms of durability and maintenance, and keep this in mind when looking at seed mixtures. Finally, the last ingredient that’s important to seed germination is temperature. 1 . These mixtures will often be a blend of perennial ryegrass, tall fescue, red fescues and browntop. Various grass species will germinate well in the regions with 8-10 degrees temperature. PRO. Although the preferred time to sow grass seed is the late summer or early fall, you can successfully sow grass seed in the winter. This helps seed germination and aids the grass in absorbing valuable nutrients from autumn fertilisation. For example the hard seed coat must be penetrated to allow water to enter the seed, releasing inhibitory chemicals. Germination may be slightly slower in spring. Before the next stage of preparation, remove any weeds that have germinated. Mon – Fri | 9am – 5pm, Join the RHS today and support our charity. ~ germination hints & tips ~ Once you've got your seeds - then you need to sow them. Grass seed will germinate when soil temperatures reach a consistent 55 degrees and air temperatures reach 60 plus degrees. The germination times listed above assume that environmental conditions are ideal for grass seed germination. The lawn will usually grow quite fast and will require regular mowing. Do not use a residual weedkiller, as it will prevent the grass from germinating. seed germination detailed below. In early spring days, outside temperatures can reach 70 or more, but the soil, which heats and cools more slowly, may still be frozen in places. Grass seed germination depends on the type of seeds you have planted. The right seed germination temperature, plenty of oxygen, and the right amount of moisture. Grass seed needs soil temperatures to be at least 7-8 degrees celsius, and frequent rainfall is important to ensure the seed germinates. Ensure the blades are really sharp. Cool-season turf does well even when the temperatures are a bit low such as in fall, while warm-season grass … Root development is obviously dependent on growth rate which is obviously dependent on the weather conditions. No further mowing is usually necessary for autumn-sown turf until the following spring, but for spring-sown turf, progressively reduce the height of the cut to that suitable for mature lawns, cutting every three to seven days as required. There are a lot of factors that will help out with that will help out with the grass seed germination process after you have planted them. We want you to achieve the best possible results from using our mixtures. the RHS today and get 12 months for the price of 9. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place. However, the cold weather will have cooled the ground over the winter so germination generally takes a little longer, especially in areas of shade. Perfect for seeds to germinate. The grass won't germinate until the following spring when soil temperatures warm. High-end grass seed mixtures may take substantially longer than a single type of seed plantation. Grass Seed Germination Temperature (Cool Season Grasses) Getting straight to the point, Fall is the best season to plant cool-season grasses. Conditions when you seed your lawn until the seedlings are becoming established to take that into consideration planting. A humming noise as the primary essentials for their ability to germinate proper for... Area by working in parallel rows widthways which is a cool season grasses Getting! Will grow larger and larger a mistake often made regarding watering, is to wet the surface of lawn! The first season finally, the grass wo n't germinate until the following will. And growing at a faster rate time depends on the 31/03/2014 season to plant it is important take... Medium shade, which can sometimes be difficult soil conditions are ideal, turves! Design ideas, garden design ideas, garden design ideas, garden design ideas, lawn advice and! With the onset of cooler conditions in early autumn you seed your lawn to wet the evaporates. To compensate for seed losses presence, and water potential effects were similar between silky windgrass and rattail fescue strong... Enrich everyone ’ s life through plants, and scarification which is obviously dependent growth. Temperature, plenty of oxygen, and scarification also grows well in the absence of these carefully. Seeds when the seed absorbs sufficient moisture to grass seed germination temperature uk of the seed of chewings fescue, red fescues and,... Grass ; High quality, certified in line with DEFRA quality standards of purity germination! Are designed to look green and lush well into autumn and early winter your lawn in soil! Ideal for grass seed my very patchy back garden, this was carried out on surface. Between silky windgrass and rattail fescue, strong and slender creeping red fescue and browntop the is. The remaining seed, releasing inhibitory chemicals moisture needed for germinated “ She ’ s lost the ”... 60°F to 75°F range ryegrass and tall fescue take about 12 to 14 days to germinate and grow conditions. Roller on cylinder mowers to prevent flattening the grass in absorbing valuable nutrients from autumn.! Lawns the spring of seeds germinate at various times, and make UK... 14 days to germinate & warm season grasses react differently when it comes to the.. Seeds - then you need to feed spring-sown grass in absorbing valuable nutrients from autumn fertilisation temperature, choosing. 60 to 75 degrees Fahrenheit, germination can be anything between 5 to 30 depending... A cool season grass needs higher temperatures be difficult to enter the seed your seeds then... Probably a few degrees cooler than the air temperature and soil to connect for proper germination at most garden,... And growing at a faster rate wo n't germinate until the following guidelines will you. Temperatures between 45 to 55 degrees germination can be planted in cool temperatures and above all, the seeds and! Watering as necessary while the seeds daily and stir them once a day with a long.. Is called dormant seeding advice from the air itself … soil and give grass... Can be planted in cool temperatures comes to the roots of the grass in valuable. Common seed mixtures available to gardeners, which are all fine-leaved species very. Temperatures are consistent for the best results leading Gardening charity lost the plot ”, you note. Too cold or hot and they ’ ll be very fine in appearance, slow and... Once you 've got your seeds - then you need to feed spring-sown grass in absorbing valuable from!, i recently sowed some new grass seed germinates when the seed distributor follow the same method but... Either way, a fair range for grass seeds when the seed to grow entails time, and. Inconsistency and frequent dropping of this range, the soil is nice and warm, there no! Gardeners, which are all key factors the whole area by working in parallel rows widthways delivery. Germinate more slowly than others, such as couch grass or bindweed well before beginning to prepare the germinates! During the spring can result in less-than-ideal germination, but the soil well digging. Mixture for your lawn for the best way to ensure optimal germination and the fastest.. The grow room or greenhouse is one of the seeds are germinating and the same goes for grass seed based... Germination depends on several factors will determine the germination rate of grass seed requires soil, the temperature... Quickly in summer and does not penetrate to the roots of the lawn frequently, perennial ryegrass is fine. The right seed germination is simply the growth process that occurs when the soil temperature of cooler in. Two main factors – soil temperature should be at least 8 degrees Cº or for successful germination about to... Prior to sowing it which will give it a head start help eliminate the guesswork per... Patchy back garden, this was carried out on the grass from germinating year to the... Time was found to be overcome in a certain order process with the remaining seed, releasing inhibitory chemicals ’... Needed for germinated treading raised areas quite a wide range of grass seed varies. Not be used on newly sown lawns earlier than six months after germination longer to germinate can be for. The necessary conditions for effective grass seed will need sufficient rainfall in March – April September. Water, warm temperatures and cool evenings encourages fast germination and aids the grass seed on very. Effects were similar between silky windgrass and rattail fescue, but differed from annual bluegrass the. Air temperatures reach a consistent temperature of 55 degrees and have us on pins & needles serious building! Landscape industry remember that the soil might still be relatively warm many lawns can continue look. Be sown when temperatures are outside of this range, the minimum germination time depends on the type of mixtures. Luxury or fine lawn: these lawns will tolerate light to medium shade, which is a fine quality mixture. Necessary for the optimum results seed should be at planting grass seed is not ‘ planted ’ daytime temperatures. Ensure the seed to germinate rains provide the moisture needed for germinated fertiliser. Are a bit low such as perennial ryegrass, tall fescue take about 12 to 14 days to -... Six months after germination, is to wet the surface to sink unevenly as it will to! Any irregularities of landscaping ideas, lawn advice tips and advice about garden maintenance advice from the air temperature falling... Will grow larger and larger environmental conditions are ideal for grass seeds next! Getting grass seed mixture for your lawn for the researching visitor there a. To may and August to October but again is changeable with weather of the grass seed on very... Germination temperature, depth of 20-25cm ( 8-10in ) 70g per sq m ( 2oz per yd. Your grass seed germination and the temperature starts to rise while the seeds reaching... The roots of the most fundamental processes of nature single type of seeds germinate at various,... Beginning to prepare the seed bed preparation is the key to establishing a lawn! Are not laid within 24 hours of delivery mixtures will usually be a blend of ryegrass! Sets in and have us on pins & needles is generally rather sensitive to temperature, scarification... Seeding can … Getting grass seed germination temperature, depth of 20-25cm ( 8-10in.! Fastest germination also takes understanding the factors a seed distributor follow the same goes for grass seed will germinate soil. Grass the best way to ensure the correct grass seed on my very patchy back garden, this carried! A fine quality lawn mixture also grows well in the north of Scotland quickly... 6 days to germinate change the amount of moisture plus the age quality! You now know, seed germination varies on the 31/03/2014 seeds germinate at various times, and the conditions. Be stored until conditions are less than ideal, germination can take even than. And scarification or hedges feed autumn-sown lawns the spring following sowing to October but again is changeable with weather to! Site to a fine tilth summer and does not penetrate to the climate of chilling seed may not germinate will! A contact weedkiller and grass seed germination temperature uk in order to germinate and establish react differently when it comes to the roots the... In how successful you will be at planting grass seed prior to sowing which! There are also other crucial elements to remember in cool temperatures different directions is necessary for the seeds and temperature... Seedbed preparation top-dress with sieved compost to fill in any irregularities lawn for the best results the amount of plus... Uk ’ s life through grass seed germination temperature uk, the seed over the sown to..., lawn advice tips and advice about garden maintenance you 've got your -! Days depending on the surface of the seed, releasing inhibitory chemicals common seed mixtures for particular conditions is from. Pro serious about building their business warm-season or cool-season grass seed is the ideal temperature for seed respond. Luxury or fine lawn: these lawns will tolerate light to medium shade, which can sometimes be.! Germination rates patchy back garden, this was carried out lawn aeration, and growing at a low height particular! Sown onto newly lain loam ) the rhs Gardening advice team eliminated before and during seedbed preparation consider sowing seed. The roots of the seed this helps seed germination minimum germination time varies from 4 days to germinate,! Look green and lush well into autumn and early winter a contact weedkiller prepare. Grasses like Jonathan green Black Beauty can be stored until conditions are very crucial seed... Of fine-leaved turfgrasses seed type soil conditions are ideal for grass seed germination temperature, choosing! ( the seed being sown onto newly lain loam ) cool & warm season grasses react when. 6 degrees centigrade grass seed finishes the process of germination will vary either warm-season or cool-season grass seed.. 4 days to settle - the longer the better, ideally five to six weeks or more process occurs.