Prairie Spirit Trail State Park

Prairie Spirit Trail State ParkPrairie Spirit Trail State Park has the distinction of being the first rail trail in Kansas, following the line of the Leavenworth, Lawrence, and Galveston Railroad. This track was originally intended to give the city of Lawrence a competitive advantage over Kansas City, but the railroad never made it to the Gulf of Mexico as planned. Construction began in 1867, and by 1871 the line had reached Coffeyville, its final destination.

The Leavenworth, Lawrence, and Galveston Railroad was in financial hot water almost from the start. In the early 1880s the line was sold and became part of the Atchison, Topeka, and Santa Fe Railroad. For many years it was operated as part of the Santa Fe, but the close of the 20th century brought changes to the railroad industry. Without enough traffic to support its use, the former Leavenworth, Lawrence, and Galveston Railroad was sold and then officially abandoned in 1990.

The Kansas Department of Wildlife and Parks acted promptly to give the railroad new life in a different form. By that time, several other states had started putting their abandoned lines to good use as recreational trails. Following suit in Kansas was somewhat controversial, as residents who lived near the proposed trail feared that the constant influx of hikers and bikers would expose them to trespassing, littering, and vandalism. But construction began anyway, starting in 1996 and continuing until 2008.

The success of this rail trail eased the fears of some property owners and paved the way for the creation of other rail trails in Kansas. A network of paths is now growing and linking with trails in other states. Meanwhile, the rail trail that started it all entered the state park system on May 28, 2010, as Prairie Spirit Trail State Park.

As of January 1, 2019, no permit is required to access the Prairie Spirit Trail.


The trail can be accessed at the following trailheads:

  • Old Depot Museum: 135 West Tecumseh Street, Ottawa.
  • Kanza Park: 216 West 13th Street, Ottawa.
  • Ottawa Trailhead: 1775 S. Princeton Circle Drive, Ottawa.
  • Princeton Trailhead: 200 block of Galveston Street, Princeton.
  • Richmond Trailhead: 200 South Street, Richmond.
  • Lake Garnett: 200 East Park Street, Garnett.
  • Santa Fe Depot: 900 South Main Street, Garnett.
  • Crystal Lake: West South Lake Drive, Garnett.
  • Welda Trailhead: Ranson Avenue and 1000 Road, Welda.
  • Colony Trailhead: East 1st Street, just east of Old U.S. 169, Colony.
  • Carlyle Trailhead: Texas Road, east side of Carlyle.
  • Iola Trailhead: 1310 North State Street, Iola.


The Prairie Spirit Trail runs through the Osage Cuestas. If you follow the path for any considerable distance, you will see a sampling of the diverse ecosystems that characterize the region. Farmland and tallgrass prairie are highlights, but along streams you will see wooded areas. The seasonal display of wildflowers is excellent.

If you are traveling the trail near dawn or dusk, you might spot some wildlife. Likely candidates include quail, owls, songbirds, rabbits, and deer.


Hunting is prohibited along the trail.


While you can’t fish along most of the trail, you are welcome to bring your fishing rod to Lake Garnett or Crystal Lake, both in the town of Garnett.

Prairie Spirit Trail State Park
© 2015 Homestead on the Range


The trail is the main attraction at Prairie Spirit Trail State Park. The route is long, but easy. Much of the trail is rock, but portions have been paved in some of the towns. Both hiking and biking are allowed.

Planning your trip? Here are the mileages between trailheads:

  • Old Depot Museum to Princeton Trailhead: 9.4 miles.
  • Princeton Trailhead to Richmond Trailhead: 6.4 miles.
  • Richmond Trailhead to Lake Garnett: 8.1 miles.
  • Lake Garnett to Welda Trailhead: 9.2 miles.
  • Welda Trailhead to Colony Trailhead: 7.8 miles.
  • Colony Trailhead to Carlyle Trailhead: 5.6 miles.
  • Carlyle Trailhead to Iola Trailhead: 4.3 miles.

Other Opportunities

Heading down the Prairie Spirit Trail? Pack a lunch—there are picnic areas available at every trailhead except the Old Depot Museum in Ottawa. Primitive campsites are also provided at some locations (no camping on the trail itself).

Take some time to discover the small towns along the way. Historic architecture, unique attractions, and more recreational opportunities await at each stop.

Organized hiking and biking events are sometimes held along the trail.

And when you come to the end of the trail at Iola, consider continuing down the Southwind Rail Trail to Humboldt for another 6-1/2 miles. This crush-rock path is easy to ride and is maintained well, and the railroad trestle over Elm Creek is considered particularly scenic. Depending on the time of year, you may also have good opportunities to view wildlife, wildflowers, and fall foliage. The Southwind Rail Trail is open to the public at no cost from dawn to dusk daily.

Helpful Resources

Prairie Spirit Trail
Information to help you plan your trip. Brochures are available for download.

Visit Franklin County
Plenty of opportunities for exploring Franklin County and the towns of Ottawa, Princeton, and Richmond, including events, arts, historical attractions, shopping, and more.

Garnett Attractions
Whether your tastes are historic, architectural, or outdoorsy, you should have no problem finding something interesting to see in Garnett or other parts of Anderson County.

Anderson County Towns
Brief histories of Garnett, Welda, and Colony.

City of Iola Attractions
Six points of interest, primarily historical.

Complete Series

Kansas State ParksKansas State Parks


The Breeding Toolbox: Inbreeding

The Breeding Toolbox: InbreedingFirst, to tackle the most controversial tool in the breeding toolbox—inbreeding.

The definition of inbreeding is simple. Inbreeding is the practice of mating two closely related animals.

The subject becomes more complicated when breeders try to define how close is “close.” Of course, all animals of the same kind are related, tracing back to a very limited number of ancestors on Noah’s ark. These animals would have inbred extensively for a few generations, but over time they produced enough descendants so remotely related that no breeder would think twice about mating any two of them.

Geneticists have provided breeders with two tools that can be very helpful in measuring how closely animals are related and how inbred they are:

  1. The blood relationship.
  2. The inbreeding coefficient.

Calculating blood relationship is very simple. It is based on the principle that half of any given animal’s genetics comes from one parent and that the other half comes from the other parent. (This principle is a bit simplistic, but good enough for everyday use.) An animal would normally have the following blood relationships to his ancestors:

  • Parent: 50%.
  • Grandparent: 25%.
  • Great-grandparent: 12.5%.

Inbreeding results in closer-than-normal blood relationships. Look what happens below, in the pedigree of an imaginary horse (any similarities to any other horse’s pedigree are purely unintentional). Dust Devil is related to Tornado twice. He receives 50% of his genetics from Tornado as his sire and another 25% from Tornado as his grandsire. Therefore, there is a 75% blood relationship between Dust Devil and Tornado. (Tumbleweed is in turn related to Tornado by a 37.5% blood relationship—half of 75%.)

The Breeding ToolboxClearly, Dust Devil is inbred because he is the offspring of a mare who was mated to her own sire. We can measure this level of inbreeding by using a number called an inbreeding coefficient. Calculating inbreeding coefficients can be complicated in some cases, but there are many software programs available to give you the numbers. If you use pedigree management software, you probably already have an inbreeding calculator handy. A free program is available from Oklahoma State University (scroll down to the calculator called “Inbreeding”). It can be a little finicky, but it works for fairly simple pedigrees.

An inbreeding coefficient basically measures the likelihood of an animal receiving duplicate genes from the same ancestor. In the example above, Dust Devil’s inbreeding coefficient is 0.25, which means he has a one-in-four chance of receiving duplicate genes from Tornado.

But if you thought that Tumbleweed’s inbreeding coefficient would be 0.125, you were mistaken. Tumbleweed is not inbred at all! His dam is not related to Dust Devil or any of his ancestors; therefore, she could not have given Tumbleweed any genes that would duplicate those he received from Dust Devil (beyond what would normally occur in a randomly breeding population of similar horses).

How It Works

Genes are inherited in pairs. One gene of the pair comes from the sire and the other gene comes from the dam.

Frequently there are different varieties, or alleles, of the same gene. For example, the difference between an Angus and a Red Angus is determined by a variation on one pair of genes, represented by the letter b. An Angus steer’s black hair comes from the B allele of the gene, while the Red Angus sports a glossy red coat due to the b allele. So if a Red Angus bull is mated to a Red Angus cow, each will give a b gene to their calf. Its genetic formula can be represented by the letters bb. Likewise, an Angus calf with two black parents will most likely have the formula BB.

But what happen if an Angus bull with the formula BB is mated to a Red Angus cow with the formula bb? Each parent contributes one gene to the calf, so it will have the formula Bb. It will look black like its sire, but it has the potential to produce red calves later on, because it has a red gene. This calf is said to be heterozygous for the black trait, meaning that it has a pair of unlike genes.

The Breeding Toolbox: InbreedingInbreeding tends to reduce the number of unlike genes in a population, particularly when combined with selective breeding. Let’s take the pedigree of our imaginary horse Tumbleweed again, or more specifically that of his sire Dust Devil. Let’s also say that we are working to eliminate the dun color pattern from our bloodline. As with the black gene in Angus cattle, the dun gene in horses comes with two alleles:

  1. D for dun.
  2. d for non-dun.

We plan to use the non-dun (dd) stallion Tornado to eliminate this color pattern. Unfortunately, we are starting out with the dun (DD) mare Cloud to do this. But never fear, we can still accomplish our goal. All of Tornado and Cloud’s offspring will have the same genetic formula (Dd) and will look dun. But suppose we breed Tornado to his daughter Storm Cloud (this is an illustration, not a recommendation). Tornado will always give a d gene to his offspring, but Storm Cloud could provide either a D or a d gene. If these two horses are mated repeatedly over time, a pattern will emerge:

  • 50% of their offspring will be Dd or dun.
  • 50% of their offspring will be dd or non-dun (we will say that Dust Devil falls into this last category).

By inbreeding we have created a population from which we can begin to breed non-dun horses, even though we started with a dun mare. How did this happen? Tornado gave his son Dust Devil one d or non-dun gene. The other d gene came from Dust Devil’s dam Storm Cloud—who in turn got the gene from Tornado!


Not surprisingly, a common use of inbreeding is to encourage uniformity in a population. Sometimes the idea is to create a whole new breed that will meet a specific set of criteria. Other times the goal is to perpetuate the desirable traits of a given animal, as was demonstrated in the example of Tornado and the d gene.

Another common way that animal breeders use inbreeding is to create two inbred lines or breeds for the purpose of crossbreeding. This practice is very common in agriculture today because it produces dramatic yet predictable results. For example, Angus and Hereford cattle are maintained as separate breeds and then crossed to produce Black Baldies for beef. This use of inbreeding will be explained further in the linebreeding and crossbreeding parts of The Breeding Toolbox series.

A few breeders use inbreeding to test their genetics. Sometimes health problems can lurk in bloodlines without detection for several generations. This is because some genes mask the effects of other genes. Notice that Storm Cloud, in the horse example above, appeared to be dun even though her genetic formula was Dd. The D or dun gene is said to be dominant; that is, it masks the effects of the recessive d or non-dun gene. Intensive inbreeding can be a way to force recessive genetic defects to come to the surface. Unfortunately, this type of experimentation is expensive and takes quite a bit of time. Today DNA tests are becoming available to eliminate the need for this use of inbreeding.


The ability of inbreeding to uncover detrimental recessive traits is precisely its shortcoming. For example, suppose that, besides the d gene, Dust Devil received two copies of a recessive genetic defect due to inbreeding. Not only would he have to be culled from the breeding program, but so would all of his full siblings, since half of them would display the defect and the other half would carry it. His dam and all of her full siblings would have to be culled, too, because they would all be carriers. Tornado would have to be culled, since he was the original source of the defect. This would mean that most of his relatives would have to go, as well. Unfortunately, breeders are human, and the financial and emotional cost of this type of culling is beyond what most of us can handle. Some carriers usually manage to escape into the breeding program and perpetuate the problem.

Furthermore, there is an interesting phenomenon known as hybrid vigor that inbreeding affects detrimentally. A certain level of genetic variability appears to be needed to ensure the survival of most animal species. Too many like (homozygous) gene pairs are associated with a loss of fertility, immune function, structural soundness, and performance ability.

To avoid these problems, some attempt to limit inbreeding is necessary. Nearly all breeders try to avoid mating siblings to each other or parents to their offspring, but beyond that inbreeding is rather controversial. The question is one of risk. Each breeder must decide for himself how much risk he is willing to accept and how ruthlessly he is willing to cull his breeding stock. This is where the inbreeding coefficient comes in handy. The higher the coefficient, the greater the risk and the more rigorously culling will have to be practiced to ensure the survival of the bloodline.

Homemade Cards

Homemade CardsLooking for a way to say it just right to that special friend or loved one? Don’t buy a card—make one!

Both adults and young people can enjoy making their own greeting cards, and Homemade Cards by Charlene Kennell offers great tips and inspirations:

  • How to find useful but inexpensive supplies.
  • How to use the elements of card design to advantage.
  • How to add special embellishments that will make each card unique.
  • How to choose a message that will touch someone’s heart.
  • How to make envelopes that will fit unconventional cards.

Along the way you will find examples, illustrations, and patterns galore to get you thinking out of the box.

Great for those who love homemade crafts, and also an excellent choice for creative children. A little booklet, but a good one!

Prairie Dog State Park

Prairie Dog State ParkSince irrigation and water supply are high priorities in western Kansas, the construction of Norton Dam and Keith Sebelius Reservoir was logical. The United States Bureau of Reclamation began work on the dam in 1961 and completed it in 1964. Kansas quickly arranged to set up a state park to provide recreational opportunities and wildlife management.

Since then, the history of Prairie Dog State Park has been fairly unremarkable. Much of the focus at the park is on local 1800s history (see Other Opportunities below).



  1. Take U.S. Highway 36 westward out of Norton.
  2. Turn south on Kansas Highway 261 and continue for about a mile to enter the park.



Prairie Dog State Park offers visitors a glimpse of the High Plains. The landscape is one of wide-open spaces and typical shortgrass prairie plants, including seasonal wildflowers. However, just enough trees are present along streams to offer shelter for wildlife.

Birds range from the greater prairie chicken of the grasslands to the bald eagle and osprey of the shoreline. Rock outcroppings attract a wide range of snakes, as well. The fauna highlight of the park, however, is its namesake, the black-tailed prairie dog. The state park was named before there were prairie dogs present, so an attempt was made to establish a colony of these entertaining little animals. This proved to be unsuccessful, but later on more prairie dogs arrived voluntarily and took up residence south of the park entrance, past the railroad tracks. This colony supports an equally interesting population of predators, ranging from badgers to prairie falcons.

Rockhounds will likely want to visit the scenic bluffs on the south shore of the lake.



Hunting is allowed in the wildlife area, but space is limited. Good populations of waterfowl, pheasant, turkey, and rabbit are present. A lucky hunter might shoot a white-tailed deer or even a mule deer. Just be forewarned that you will have plenty of competition from other visitors, particularly at the beginning of the season.

For archery practice, try out the range just west of Branded Cedar Campground.

Prairie Dog State Park
© 2015 Homestead on the Range


The fishing in Keith Sebelius Reservoir is superb, no matter what your preferred method is. The best opportunity is wiper, but your odds are good for catching walleye, crappie, black bass, and both channel and flathead catfish. Also try your luck at bluegill and carp.



Prairie Dog Nature Trail: This walking trail is 1 1/2 miles long and starts at the prairie dog town. You will then head toward Meadowlark Campground for a good view of the lake. Interpretive signs point out interesting features of the park.


Other Opportunities

Want to learn more about prairie dogs? Stop by the park office for more information.

Near the park office is the one-room Hillmon Schoolhouse, built in 1886 about two miles south of the state line. This was moved to the state park and dedicated in 1969.

Also of historical interest is the last adobe house in Kansas that has remained in its original location. It was constructed in 1892 and has been preserved for visitors to see. It is located just northwest of Prairie Dog Campground.


Helpful Resources

Prairie Dog State Park
Information to help you plan your trip. A brochure is available for download.

Hillmon School
A little more about this fascinating old schoolhouse from the official Kansas tourism site.


Complete Series

Kansas State ParksKansas State Parks


The Breeding Toolbox: Introduction

The Breeding Toolbox: IntroductionIf you breed animals of any kind, whether they be dogs, goats, or cattle, hopefully you have a goal.  Maybe you want to preserve a rare breed, or maybe you just want to perpetuate the good qualities of that favorite laying hen.

Once you have set a goal, the next step is to develop a path for reaching that goal.  Before you dig in and start planning, however, it might be a good idea to look over the four tools available to every animal breeder, no matter what species they raise.

The four tools are:

  1. Inbreeding.
  2. Linebreeding.
  3. Linecrossing.
  4. Crossbreeding.

It is important to remember that there is no such thing as a silver bullet.  Each of these four tools is exactly that—a tool, a means for reaching a desired end.  Just as a hammer cannot solve all of the world’s construction problems, neither can any one of these tools solve every genetic problem that comes along.  Every tool has its own unique set of strengths and weaknesses.

Throughout this series, you will learn more about each tool in the breeding toolbox, how and why it works genetically, and how to capitalize on its advantages while avoiding its pitfalls as much as possible.

For easy navigation, we have linked to each post below.


Complete Series

InbreedingThe Breeding Toolbox: Inbreeding


LinebreedingThe Breeding Toolbox: Linebreeding


LinecrossingThe Breeding Toolbox: Linecrossing


CrossbreedingThe Breeding Toolbox: Crossbreeding


Our Vitamin Guide—Updated!

Our Vitamin Guide—Updated!We have updated our vitamin guide to include country pets, those special cats and dogs that share our lives and help us out around the farm.

In addition to information on vitamins in livestock nutrition, you will now find details applicable specifically to pets:

  • Natural sources of vitamins tailored to carnivores.
  • Causes of vitamin deficiency unique to cats and dogs.
  • Symptoms that pets are unlikely to share with livestock.
  • Causes and symptoms of toxicity specific to small animals.
  • Medicinal uses of vitamins that have been successful in pets.

The usual cautions apply.  Content regarding medical conditions and treatment is provided for general information purposes only, and is not to be construed as legal, medical, or professional advice.  Please consult your veterinarian for advice regarding your specific animal’s needs.

Pomona State Park

Pomona State ParkSeveral historical facts make Pomona Lake unique.  First, it is just a few miles south of the old Santa Fe Trail.  Second, it gives Osage County, Kansas, the distinction of being the only county in the United States with two federal reservoirs (Melvern Lake at Eisenhower State Park is the other reservoir in the county).

Like many Kansas reservoirs, Pomona Lake was authorized in 1954.  The United States Army Corps of Engineers began work on the project in 1959.  The dam was completed in 1963, but it took another two years for the lake to fill up.  Shortly after the dam was built, a state park was created to provide recreational opportunities for visitors.

Today, Pomona State Park is known for being a true getaway, with its quiet natural scenery and its relatively low traffic level.



  1. Take Kansas Highway 68 west out of Ottawa for about 13 miles.
  2. Continue straight onto Kansas Highway 268 and drive another five miles (follow the signs).
  3. Turn right onto Kansas Highway 368 and continue for about a mile to enter the park.



Pomona State Park is a prime example of a landscape that has been restored to native Osage Cuestas scenery.  Much of the park is covered in tallgrass prairie, while streams and shoreline foster oak, hickory, dogwood, hackberry, cottonwood, and American elm trees.

This park is considered an excellent place to see a variety of wildlife, particularly birds.  Watch for shorebirds, waterfowl, woodland songbirds, and bald eagles.  Also keep your eyes open for bobcats, coyotes, and squirrels.  Not all of the wildlife is pleasant, though—look out for copperheads and rattlesnakes!



Most of the public lands surrounding the lake are available for hunting.  Potential game includes quail, pheasant, turkey, rabbit, squirrel, and deer.  Waterfowl is also abundant in the marshes near the lake.



Pomona Lake offers outstanding opportunities to catch crappie and channel catfish.  But don’t overlook the other possibilities.  Some trophy-quality wiper and flathead catfish have also been caught here.  In early spring, try fishing for white bass in Dragoon Creek.  Largemouth bass fishing can be a little slower, depending on the season, but is still worth a try.

For something a little different, try ice fishing in the winter.  A favorite summer event is the Kids’ Fishing Derby held on the first weekend of June every year.

Pomona State Park
© 2015 Homestead on the Range


  • Deer Creek Nature Trail: Located in Outlet Park, this quarter-mile trail is for hiking only.  A brochure is provided to help you identify the trees growing along Deer Creek.
  • Witches’ Broom Nature Trail: Another woodland trail, this one is half of a mile long and is located in 110-Mile Park.  Interpretive stops will acquaint you with the native flora and fauna.
  • Rising Sun Trail: This half-mile loop circles through the Ah-Ket-Ah Area and is open for hiking and biking.  You will mostly explore the timber near the lake.
  • Buckbrush Trail: Offering both hiking and biking, this path is over 3/4 of a mile one way, one of the trailheads being at Burning Heart Campground, the other at a nearby picnic shelter.  The trail roughly follows a treeline marking the edge of the state park.
  • Hedge-Wood Trail: A handicapped-accessible linear trail that is also open for hiking and biking.  This route is just over a mile long one way and connects the park entrance with Big Bear Campground.  Much of it is through trees.
  • Blackhawk Multi-Use Trail: This trail is over 30 miles long, offering a challenging route for hikers, bikers, and horseback riders.  The path can be muddy and overgrown, but it showcases a variety of scenery near 110-Mile Cove, including both woodlands and grasslands.  Exercise caution in hunting season.


Other Opportunities

Park staff work hard to provide visitors with a variety of interesting events.  Some of these activities include fishing contests, fireworks displays, church services, hiking events, and free coffee and donuts.

Exploring the lake with all kinds of watercraft ranging from canoes to sailboats is popular at Pomona State Park.  However, there are many underwater dangers, so be careful.

In winter, visitors are welcome to try snowshoeing and cross-country skiing along the shore.


Helpful Resource

Pomona State Park
Information to help you plan your trip.  A brochure is available for download.


Complete Series

Kansas State ParksKansas State Parks


What Makes Some Cucumbers Bitter?

What Makes Some Cucumbers Bitter?All cucumber plants contain a substance known as cucurbitacin, which tastes very bitter and is toxic when concentrated.  Normally, cucurbitacin is found in the roots, stems, and foliage of the plant, but in times of stress it may creep into the cucumber fruits, as well.

Usually the cucurbitacin content of a cucumber is so low that the chemical cannot be tasted and no side effects (upset stomach, burping, cramps, diarrhea) occur from eating it, but many gardeners have had the misfortune of picking cucumbers with a distinctly bitter flavor.  What causes this?

Experts are not entirely in agreement on the cause of bitterness in cucumbers.  It appears that flavor is produced by a complex interaction of circumstances.

Here are some of the factors which influence cucumber taste:

  • Variety.  Choose a cucumber variety that is low in cucurbitacins.  Burpless cucumbers have less obtrusive levels of the offending chemical, while bitter-free cukes never have cucurbitacins in the fruit.  Gardeners have consistently proven that variety is the most important factor affecting taste.
  • Temperature.  Excessive heat, unseasonably cool weather, and wild swings of temperature can all stress cucumbers, increasing cucurbitacin levels.  If your summer highs are typically in the mid-90s or higher, provide some shade for your cucumbers.  If cool weather is consistently a problem, choose a variety that doesn’t mind lower temperatures.  Unfortunately, there is little that a gardener can do about variable weather, except choose a more forgiving variety.
  • Water.  Either drought or irregular periods of wet and dry weather can increase cucurbitacin levels in the cucumbers.  Don’t let your plants go too long without water.  Keeping the soil slightly moist (but not soggy) at all times is recommended.  Mulch helps to even things out.
  • Soil health.  Healthy soil produces tasty cucumbers.  Check your soil fertility and pH to see if this could be the source of the problem.
  • Competition.  Weeds are stressful to cucumbers.  They compete for valuable water and nutrient resources, and they harbor insect pests.  Keep the weeds in check.  For the same reason, make sure you space your cucumbers according to the directions on the seed packet.
  • Ripeness.  As cucumbers mature, cucurbitacin levels rise.  Don’t let your cucumbers get too big.  Most slicing varieties should be picked when they are between six and eight inches long.
  • Storage.  The longer a cucumber sits in the refrigerator, the more its cucurbitacins will concentrate.  Try to eat your cukes while they are still fresh.

If you experience weather conditions that are likely to stress your cucumbers, take a few steps to reduce the quantity of cucurbitacins that you are going to eat.  Most of the chemicals are concentrated at the ends (particularly the stem end) and directly under the skin of the cucumber.  Peel the cuke well, chop an inch off the stem end, and slice the other end off, too.  If it still tastes very bitter throughout, the plant is either in bad health or genetically predisposed to bitterness.  You might want to pull it up and try again next year, preferably with a different variety.

Keep in mind that, while many factors affect cucumber flavor, cucumbers will not become extremely bitter unless they are genetically predisposed to do so.  Some varieties never develop a bitter taste even under adverse conditions.  Therefore, while you should be careful to keep your plants healthy through proper watering and soil building, choosing a variety better suited to your taste buds and climate is the only reliable solution.