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Lawns and Lawn Soil Preparation

Question: After hydroseeding, when can I expect to mow for the first time?
Answer:  Generally, if conditions are right, you can expect to mow your lawn for the first time about 3 to 3 ½ weeks after hydroseeding (sometimes sooner but this is the general time range). Make sure you stop watering your grass for a day or two, if possible, to avoid causing ruts in your lawn.  Riding lawn mowers are not advisable until grass is firm and has an established root system.  Be careful to not let your lawn get too long before you mow as it will be extra moist (which can cause ruts) and may be yellow or light green after cutting this is usually only temporary.  The general rule is to mow your lawn for the first time when it gets to about 3 1/2 - 4 inches.  After that, 2" to 2 /2" is suffice for most grasses.  Try to not cut more the 1/3 of the grass blade during each mowing.  Lawns with deep columns of sandy loam may need more time before mowing until sufficient root growth occurs through the soil profile to firm the soil to the extent that a mower can be used. 
Note:  Please read irrigation section below about watering your newly hyroseeded lawn
Question: How late in the year do you hydroseed?
Answer:  We generally do not prefer hydroseeding past October 15th.  Sooner than this is better.  Many variables come in to play when you start going into this time frame.  Colder weather can slow grass growth and give weeds a better chance to invade your lawn.  Also, heavy rains can cause the seed to float and be displaced.  Its a tricky time because homeowners usually have less watering involved in the fall as they can rely on rains to subsidize irrigation.  IF hydroseeding must be done in late fall or even winter, we add extra seed to the mix.  Also, conditions are cooler so you don't have to water your lawn 3 times a day (initially) like the summer.  Erosion control or wetland hydroseeding is better done in the fall when there is no supplemental irrigation.  This is due to the fact, that once the seed takes in water, it will most likely start to germinate.  If you get some rain and then a period of dry sunny weather, it is possible that you will have lower germination rates.  We do not recommend hydroseeding in the late fall or winter but if you still prefer hydroseeding in this time period you can expect the following:
1)  Very slow and sporadic germination
2)  Disease susceptability
3)  Poor root growth
4)  Higher than normal weed populations - especially annual bluegrass (Poa annua)
5)  Additional spot hydroseeding in the spring

Question:  I have weeds in my hydroseeded lawn?
Answer:  Weeds are common in newly hydroseeded lawns as the soil itself contains generations and generations of stored seeds from mutlitple species and this seed bank is endless.  These seeds are just waiting for some light to germinate.  Sources of weeds can be topsoil, native soil, wildlife, and wind blowing in seeds from adjacent areas.  Some weed seeds live in the soil for years (sometimes hundreds of years) and can be easily brought to the surface via tilling.  Unfortunately, tilling is crucial for proper soil preparation and is probably the most common source of weed growth.  We always till the soil unless we are importing thick columns of sandy loam but in most cases the subsoil should be tilled.  Actually, earthworms can also bring weed seeds to the soil surface but some lawns have much higher populations of earthworms than others (and they are good for the soil eventhough they do cause bumpy areas to various degrees).  After your lawn has been mowed about 3 or 4 times, a broadleaf weed treatment can be done to control broadleaf weeds.  We will provide this service for you if we did the soil preparation.  Keeping your lawn mowed and fertilized regularly (but not too much!) will help control lawn weeds to a great extent.  Fall fertilization is important to help keep your lawn healthy and strong because the winter is a good time for weed invasion because of declined lawn vigor.  Try to keep weeds such as Annual Bluegrass and Creeping Bentgrass out of your shrub beds.  Note:  We always use certified grass seed.  Sometimes if we are replacing old lawns with a large array of weeds such as bentgrass, velvetgrass, or annual bluegrass we use a delayed planting to avoid regermination.  This scenario is outlined as follows:
1)  Kill off old lawn with broad spectrum herbicide (sometimes takes more than one application and more than one type
     of chemical)
2)  Sod -cut and remove old grass
3)  Till area using hand tiller or tractor and establish rough grade (this is also the time we till in amendments into the soil 
4)  Haul in loam if needed (depth will vary) and establish finish grade (depending on depth of loam, we may also apply
     amendments at this time)
5)  Water area for a period of 10 days to 2 weeks to encourage weed germination (seeds) or vegetative regrowth from 
     from plants that weren't completely killed of (this can especially occur with velvet and bentgrass)
6)  Kill seedlings or growth as it emerges (try to kill seedlings and re-growth when small to avoid removing clumps of 
     dead vegetation again)
7)  Before hydroseeding, lightly rake soil surface to break up any hard layers and subsequently hydroseed
The biggest issue with this technique is that it takes a while to finally get a ornamental lawn, but sometimes its the best course of action to combat these difficult to eradicate weeds.  If we are renovating a lawn with annual bluegrass infestations, we almost always use this technique as annual bluegrass can set seed below mowing height. Of course, this technique isn't as necessary with sod as it is with hydroseeding because your eliminating the light seedlings need to grow by putting down a blanket of soil and grass.  Its still possible that regrowth from the velvet or bent grasses can occur between the sod gaps but this rarely occurs.  This technique is the most important for jobs where native soil is being used or where very thin columns of sandy loam are being installed
Question:  Is fall fertilization important?
Answer:  The simple answer is yes .  Fall fertilization is usually done around the time frame of mid-October through mid-November.  Grass roots grow for a period of time even when top growth has subsided.  These roots store the nutrients and utilize them when conditions are conducive to grass growth in the spring.  Any fertilizer helps, but fertilizers high in phosphorus help encourage root development which results in higher amounts of stored nutrients.  This statement is assuming that their are not sufficient quantities of phosphorus in your soil already.  However, I think this is more important to put down fertilizer containing phosphorus initially.  The reason for this is that we till the subsoil before putting down loam (the loam may be low in phosphorus).  Your sub soil most likely has sufficient quantities of phosphorus as the sandy loam may not.  Eventually, your lawn will grow into the subsoil depending on the depth of the loam.  Keeping your lawn healthy and fertilized going into winter is one of the best cultural practices you can do for your lawn.  In the winter, lawns are at their lowest vigor and are more susceptible to weed encroachment and moss.  Its more difficult to get phosphorus to the root zone of grasses because its highly immobile in the soil.  This is why newly seeded or sodded lawns benefit greatly from the phosporus to develop a better root system which translates into turf that can hold more nutrients for longer periods of time and require less water imputs.  On established lawns, core aeration followed by fertilizer application can get phosporus into the root zone more effectively.  In general, in my opinion, using products called fall fertilizers doesn't make a difference compared to your normal lawn fertilizer at anytime of the year on established lawns.  The one exception to this rule is that some organic fertilizers need warmer soil temps for the soil microbes to start releasing the nitrogen into the soil.  As a side note, many organic amendments (which are usually tilled into the soil) have beneficial amounts of phosporus and potassium.
Question: What are signs of an unfertilized turf?
Answer:  The following is a few signs to look out for:
1)  Yellow/lime green or browned leaf blades
2)  High weed/moss populations
3)  Thinning of turf - this is what encourages weed populations
4)  Dark green and yellow or duller green areas in a lawn (especially in patterns) - this is usually a sign of uneven 
     fertilizer placement 
5)  Much higher percentage of disease/insect problems 

Question: How do you control bentgrass and velvet grass in a lawn?
Answer:  Bentgrass is a very common albeit very troublesome lawn weed here.  It spreads fast and develops an unaesthetic look when mowed too high because of its propensity to develop heavy thatch.  Unfortunately, broad spectrum herbicides are the most effective way of getting rid of bentgrass.  However, this will leave brown spots in your lawn until desirable grass is put in its place.  I suppose mechanical removal is possible but the chances of getting the entire roots system out are minimal and it will re-grow fast from small amounts of roots/stems left.  Velvet grass spreads fast, just as bentgrass, and is very un-appealing in a lawn because of its distinct color difference from other desirable lawn grasses.  Another troublesome weed is annual bluegrass (Poa annua) which really isn't an annual if its watered in the summer.  This grass spreads easily because of its ability to flower and set seeds at heights lower than cut points on lawn mowers (it can even set seed of golf course greens).  Its easy to spot this grass because of its light green color and it usually has seed heads and/or flowers visible on the plant.  The jury is still out on chemicals that can eliminate this grass in lawn settings.  This grass likes to grow in planter beds along the edges of lawns so be sure to eradicate it before it sends seeds into your nice new lawn.  Just like bentgrass and velvet grass, broad spectrum herbicides or hand pulling are the best course of action.  Hand pulling can have better results because, as opposed to bentgrass and velvet grass, this grass is a bunch grass and doesn't spread via stolons or rhizomes so your not leaving underground growth that can re-sprout.  Be careful however as their could have been seeds released around the plant before you remove it.  Sometimes hand pulling plants with seed heads drops a large number of seeds around the area.  If the bluegrass area is large and your not planting sod in its place, we recommend watering the area to force any subsequent germination before re-seeding with turf grass.  In conclusion, this grass loves winter conditions and thrives at times when turf grass doesn't.  It doesn't seem to be very drought tolerant and usually dies in the summer without supplemental irrigation.
Question: I water my lawn frequently but the my lawn is browning up and the soil is still dry?
Answer:  The possible cause of this is soil compaction.  Look for water puddling in your lawn.  Compaction is a common occurrence in lawns and happens quicker if lawns are prepared in wet soil with heavy traffic such as foot or equipment.  Compaction in lawns shows up quicker and earlier in the season on compacted sloped soils.  Excavating soil, tilling in amendments, and aerating are all possible ways of reducing compaction.  If you want to excavate the soil, be sure to take out enough to provide a good rooting base for your grass.  We recommend at least 5" -6" of good rooting space for your new lawn.  In conclusion, soil preparation is best not done in winter because tilling is usually not possible.  One exception to this is excavating 5"-6" of native soil and replacing it with loam or a loam and compost mix.
Question: How do I control moss in my lawn?
Answer:  Moss is a tough organism and out-competing it is the best way to keep it at bay.  Moss loves cool, wet, and shady environments and at sometimes of the year lawns can have all three conditions.  It can also de-hydrate, go dormant and come "back to life" when better growing conditions occur.  Moss is usually at its best in our lawns from fall through mid-spring.  The best thing to do with moss control is to prevent it from growing is by providing conditions that make it hard to get established in your lawn.  Here is a list of moss preventative measures (note: moss is almost un-avoidable in some situations especially in shadier areas but there are certainly things you can do to keep it at bay until warmer sunnier weather arrives.
1)  Keep your lawn dense and healthy through proper fertilization especially in the fall.  A fertilized lawn is dense which gives less space for the moss to grow and prosper.  Over fertilized lawns can actually acidify the soil so make sure you don't fertilize more than what your lawn needs.  I actually like to wait until my lawn starts shown signs of reduce color before I fertilize.
2)  Do you have bad drainage?  Aeration is a good tool to use to improve drainage as moss loves wet soil conditions.  If that doesn't help, removal of existing soil may be required assuming all other cultural practices are met.  Aeration also helps your grass which in turn keeps it more competitive against moss
3)  Do you have a lot of thatch?  Excessive thatch build-up can act like a sponge even on otherwise well drained sites.  Thatch your lawn in the spring as it will recover quicker than the fall.
4)  Moss can survive in the summer if lawns are irrigated.  Usually lawns in shadier conditions have this problem.  Moss doesn't seem to be a big fan of full sun in the warm summer months
5) Are some of your lawn areas in too much shade?  You can either plant more shade tolerant species such as tall fescue or the fine fescue group.  Another possibililty is allowing more light to your lawn area by pruning trees or removing objects causing the shade.  As a last resort, you could always turn sections of your lawn into bed areas.  This is usually only done if small border sections of your lawn are in the shade.
6)  Surface lime application can sometimes work by raising the surface PH of the soil creating a less conducive environment for moss growth
7)  The closer you get to moss growing season, try not to mow your grass too short as this could create openings.  I've seen this happen with bumpy lawns that have very short areas of grass after mowing or lawns that have excessive earthworm "mounds"
In conclusion, good cultural practices, good light conditions, and good drainage are your best ally against moss.  If you already have moss, mechanical removal and chemical control are possible.  We use ferrous sulfate to kill moss but be careful around concrete because like some lawn fertilizers, ferrous sulfate contains iron (moss hates metals such as iron and copper) which can leave a rust colored stain on your concrete.  Moss killers come in many formulations with liquid and granular being the most common.  Thorough coverage of the moss foliage is a must.
Question:  What is the best type of grass for shadier areas?
Answer:   The fine fescue group, which comprises many species and cultivars, is considered one of the most “shade tolerant” grasses on the market.  Please note that I am using the word "tolerant" loosely here as most ornamental grasses would prefer sun.  Unfortunately, it doesn’t do as well in wet shadier areas.  Also, it can develop a fair amount of thatch overtime.  Sometimes seed mixes contain a combination of perennial ryegrass and fine fescue in an attempt to get the fast germination of perennial ryegrass and the shade tolerance of fine fescue.  Overtime, the perennial ryegrass dominates the sunny areas and the fine fescue takes over the shadier areas assuming they are not overly wet (especially in the winter).  Overtime, there can be fairly distinct texture differences in your lawn by using this mix. 
Question:  How often should I fertilize my lawn?
Answer:  This is a difficult question to answer because all lawns are different in terms of soil type and texture, type of fertilizer (quick release, slow release, or organic), age of lawn, depth of root system, frequency of irrigation (over-watering will cause a shorter result), time of year, and type of grass.  Lawns are generally fertilized 3 to 6 times a year.  Response to fertilizer usually last from 3 to 7 weeks but can last longer.  Perennial ryegrass is the most common type of grass used in the Pacific Northwest but it’s also one of the most fertilizer demanding grasses available.  Make sure you water your grass after fertilization as small amounts of moisture (such as morning dew) on the grass blade can cause the fertilizer to stick to the grass blades and subsequently cause burning.  Un-fertilized lawns progressively lose their dark green color and become more susceptible to dead thatch build-up, weed encroachment, and in some cases, disease and insect damage.  It is true that returning clippings back to soil via the use of a mulching mower does reduce the frequency of fertilization (sometimes substantially).  Make sure you using a mulching mower and not a regular mower that leaves clumps of clippings on top of the grass as this will reduce sun to the grass foliage and cause yellowing and die off.  Read the directions regarding application rates on your fertilizer bag and also read the directions that come with your fertilizer spreader whether its a drop or rotary spreader.
Question:  Are soil amendments necessary when preparing the soil for grass installation?
Answer:  Soil amendments are never a bad idea but their effectiveness diminishes overtime. Organic amendments add to soil fertility and are very effective when tilled into heavy soils.  When tilled into sandy soils such as common used sandy loam, they can increase water retention and fertility in the soil.  The biggest problem with amendments is they can cause sink spots in a new lawns when they start decomposing if they are not spread and tilled evenly.  The long term benefits of organic amendments diminish overtime but its certainly plausible that supplemental fertilizer inputs will be reduced at least initially.  In closing, if applied right, amendments have a useful purpose in the landscape just not long term effects but they can certainly get your lawn off to the right start.
Question:  What are the benefits of sod vs. hydroseeding?
Answer:  The benefits of sod are numerous.  One of the best things about sod is that you get an instant lawn as opposed to waiting 3 or more weeks to get a lawn that is long enough to mow.  Also, it’s very difficult for weeds to grow with sod because of the denseness and soil shading that sod provides.  Sod generally requires less initial watering start times than hydroseed and establishes quicker.  After about a week, sod roots should already be infiltrating the soil. Mowing can commence about 2 weeks after sod installation.  Sod should be fertilized about 4 or 5 weeks after installation as we initially put fertilizer down on the soil surface.  The two biggest negatives about sod is its tendency to initially dry out a bit when it’s adjacent to concrete.  As long as the seams between the sod don’t dry up and shrink, it will recover rather quickly.  The other negative aspect about sod is that it’s much more expensive than hydroseeding from a material and labor standpoint.  Generally, sod is initially watered two times a day in the summer and up to three times a day if the weather is very hot.  It’s not advisable to install sod when abnormal hot weather conditions are around.
Other Lawn Facts
  • If your just thatching your lawn, aeration can be an important asset after thatching, especially if your thatching an old compacted lawn
  • Tall fescue has better drought tolerance than most other common used grasses but it still takes sometime to gain “drought tolerance” while its getting established
  • Lime is used to raise soil PH, but most of the time it’s unnecessary.  This is because grasses like perennial ryegrass grow well in our native soil PH ranges.  If you’re planning on using lime its best to till it into the soil.  Soil tests can be done to test your soil’s PH and their are many local companies that can do this for you. Thick columns of sandy loam can have a low PH however but PH of loam or sandy loam can vary greatly.  If you want lime added, it is best done before soil preparation and seeding so you can get it mixed better in the soil.
  • Never use new bark mulch as a soil amendment or mulch for newly seeded lawns.  Use sawdust or other organic mulches such as chopped straw.  Aged bark is less likely to rob soil of nitrogen but may still be too heavy for mulching seed unless its fine bark.  Cover seed lightly - about 1/8" - 1/4" thick. 
  • Sandy loam is a commonly used top soil for lawn renovations.  Its great for grading and the newly developing grass roots grow well in it.  Sometimes only an inch or two is applied because of feasibility but we always till the existing subsoil prior to loam placement to give the grass roots an efficient rooting soil column.
  • If your wanting your less than desirable soil taken out and replaced, we recommend a 5” -6” layer of sandy loam or other good textured soil to be placed and rolled.
  • Children’s toys, swimming pools, and other objects left on a lawn will cause your lawn to yellow and eventually die if left for long periods of time.  Sometimes lawns will yellow within 3 days if an object is not removed.
  • In the fall, it is very important to keep leaves off your lawn as much as possible. Leaving leaves on your lawn will cause the lawn to yellow and eventually die out.  This can be a cumbersome task but dead spots in lawns caused by leaves are one of the most commonly encountered problems we see.  Some trees with fine leaves like honey locust don't cause as much of a problem as large leaved trees such as oaks, maples, london planetree, cottonwoods, and tulip tree. 

Question:  Do you have to water drought tolerant plants after they are planted?
Answer:  Even plants considered drought tolerant don’t get that way until their roots become established in the soil.  Plants that retain water in their leaves generally have quicker drought tolerance. Most newly installed plants require the same amount of water no matter what the type of plant it is.  There are exceptions to this but this is the general rule.  Obviously, newly planted plants installed in shade will require less water.  Also, mulch is a big factor in how much water plants need.
Question:  I water my plants frequently but it looks like they are drying out?
Answer:  Actually, plants that die from lack of water can also have the same symptoms as plants that receive too much water.  This is basically a product of root death.  When there is not enough water in the soil, roots die off causing the foliage to de-hydrate.  When there is too much water in the soil, the roots are deprived of oxygen and will also die. This also gives the plant a “dried out” appearance because the dead roots are not providing water to the foliage. Rhododendrons/Azaleas, Arborvitae, Daphnes and many others are notorious for perishing from over watering and under watering.

Other plant facts:
  • Smaller plants established quicker than larger plants
  • Red Maples (and many other maples species) are notorious surface rooters, be careful when planting them in close proximity to concrete sidewalks or other concrete surfaces
  • Plants can still dry out in winter if their roots are not getting enough water.  Tree canopies above plants often limit rain water getting to the root zones.  The plants themselves can divert water away from their roots zones if they are newly planted and have a limited root zone to start with. This is especially the case with conifers.
  • Balled and Burlapped plants are best watered with drip irrigation.  If drip irrigation is not available, installing a small water berm around plants (2” -4”) can help slowly percolate water into the heavy textured root ball.  Mulch is also important with B & B plants.
  • Balled and Burlapped plants often have reduced growth the following year after planting
  • Balled and Burlapped plants generally establish slower in the landscape than containerized plants
  • If possible, stakes are best removed after a year or so after planting.  Plants that continuously use stakes for some support develop weaker trunks in time.  By allowing the trees to sway in the wind, they will build more strength to their trunks.  Some plants still may need stakes after a year, especially trees that are planted bareroot or plants that have a heavy canopy with limited trunk strength. Shrubs pruned into tree form are notorious for needing extended staking (Hibiscus syriacus, Hydrangea paniculata, roses,Viburnum lantana, and Wisteria are all examples)

Question:  How often do I water my hydroseeded lawn?
Answer:  This question is hard to answer because too many variables are involved.  The old saying water for longer sessions at a time with longer durations between waterings is very true.  This is because a deeper grass root system is encouraged with water farther down in the soil profile. The problem is that some lawns can only take so much water before the soil hits its water holding capacity and the rest of the water runs off.  With newly hydroseeding lawns, you need to water more frequently to keep the mulch damp around the seed.  Generally, with hydroseeding in the warm weather we set the clocks to run 3 times a day until germination commences.  This is to keep the wood fiber mulch moist.  After that, clocks are turned down to 1 or 2 times a day depending on current weather conditions.  As a guideline, once your grass is about an inch tall, you can reduce frequency of watering.  Your grass may still need the same amount of water applied at a given time but the amount of watering times can be reduced.  Watering your lawn 3 times a day is too much wasted water after your grass has started growing.  Once your grass has started growing, it shades the soil better and helps reduce soil evaporation.  Finally, as the warmer weather wanes in late summer, clocks can be turned down to 1 time a day.  Always, turn your clocks off in wet weather and some new lawns don’t even need water in the summer if it’s cloudy and cool outside. Lawns in shadier areas require much less water than lawns that receive full sun.  If your lawn is sloped, we try to use sprinkler head nozzles with lower precipitation rates so that less water is applied at a time to encourage the water to percolate into the root zone rather that running off.
Question: What are the benefits of using drip irrigation as opposed to sprinkler irrigation for plants?
Answer:  Generally, we prefer to install drip irrigation in bed areas to avoid the potential of plants growing up and blocking sprinkler heads.  This problem can be alleviated somewhat by using 12 inch pop-up sprinkler heads or by installing sprinkler heads on risers.  However, risers can cause an un-aesthetic look to the landscape and they are easily vandalized or broken.  Another problem with watering shrubs beds with sprinkler heads is that top heavy plants such as many perennials and shrubs with large flowers can tend to droop down with all the water collecting on leaf and flower surfaces.  Larger growing ornamental grasses can also have this problem eventhough some tend to flop over when the fall rains arrive (this is very common with some of the larger growing species of miscanthus sinensisThe one problem with drip irrigation is that it can cause denser more limited root systems.  Down the road, the drip irrigation may require more emitters to cover the expanding root system of plants, especially trees.  This is an easy thing to do however.  Pre-emitted drip irrigation is usually installed to cover large sections of soil in somewhat the same way sprinkler heads would.  Dense plantings are best done with pre-emitted drip rather than individual plants with single emitters.

Other irrigation facts:
  • Its advisable to not water plants with lawn irrigation zones because plants generally require less water than lawns, especially mulched plants.
  • Irrigation nozzles with lower precipitation rates are advisable in sloped areas to discourage water running off to the bottom of the slope.
  • Rotor sprinkler heads and fixed spray heads should never be installed on the same zone because of their different water application rates and run times.  You will ultimately have areas over-watered or under-watered.
More frequently asked questions to come………………………..