‘Potomac’, also known as ‘Acme’, ‘Early Melrose’, and ‘Essex Hybrid’, is an heirloom variety of apple-shaped tomato. The fruits are round, flat on the top and bottom, and indented on the blossom end. Each fruit weighs 4-6oz, and hangs in clusters of 4 to 6. Indeterminate. The two main growth habits of tomatoes are determinate (stops growing when end buds set fruit, crop is produced all at once – bush types) and indeterminate (continues to grow and set fruit – vine type)Tomatoes require full sun and grow best when day temperatures are between 65 and 85 degrees. Flowers will not set fruit if night temperatures drop below 55 degrees F. Tomatoes may be started from seed or transplants. Transplants can be set out no sooner than 3 weeks after your last average frost date. Soil should be warm, fertile and well-drained. Work in a complete, balanced fertilizer at a rate of 1lb/100 SF. Plants should be set out on a cloudy day or late in the afternoon so they will not stress. Dig hole so that plants will be buried up to their first leaves. If stems are really long, plant in a trench with plant laying on it’s side. Leaves will turn upright within a week. Space plants about 3 inches apart. Fertilize again around midseason. Provide plenty of even water until fruit starts to color, then reduce water so that fruit will be more flavorful. Harvest tomatoes when they are in full color for most flavor. For more information see the article “Seeing Red.”Important Info : It is imperative that vining or indeterminate tomatoes are staked. Determinate or bush types benefit from caging or staking too, though not as necessary.
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Size: Height: 6 ft. to 20 ft.
Width: 0 ft. to 0 ft.
Plant Category: annuals and biennials, vegetables,
Foliage Characteristics: medium leaves,
Flower Color: whites, yellows,
Tolerances: heat & humidity,
Bloomtime Range: Early Spring to Late Summer
USDA Hardiness Zone: undefined
AHS Heat Zone: Not defined for this plant
Light Range: Full Sun to Full Sun
pH Range: 5.5 to 7
Soil Range: Mostly Sand to Clay Loam
Water Range: Normal to Moist
FertilizingHow-to : Fertilization for Annuals and Perennials
Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.
LightConditions : Full Sun
Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.
WateringConditions : Moist and Well Drained
Moist and well drained means exactly what it sounds like. Soil is moist without being soggy because the texture of the soil allows excess moisture to drain away. Most plants like about 1 inch of water per week. Amending your soil with compost will help improve texture and water holding or draining capacity. A 3 inch layer of mulch will help to maintain soil moisture and studies have shown that mulched plants grow faster than non-mulched plants.
PlantingHow-to : Preparing Garden Beds
Use a soil testing kit to determine the acidity or alkalinity of the soil before beginning any garden bed preparation. This will help you determine which plants are best suited for your site. Check soil drainage and correct drainage where standing water remains. Clear weeds and debris from planting areas and continue to remove weeds as soon as they come up.
A week to 10 days before planting, add 2 to 4 inches of aged manure or compost and work into the planting site to improve fertility and increase water retention and drainage. If soil composition is weak, a layer of topsoil should be considered as well. No matter if your soil is sand or clay, it can be improved by adding the same thing: organic matter. The more, the better; work deep into the soil. Prepare beds to an 18 inch deep for perennials. This will seem like a tremendous amount of work now, but will greatly pay off later. Besides, this is not something that is easily done later, once plants have been established.
How-to : Preparing Containers
Containers are excellent when used as an ornamental feature, a planting option when there is little or no soil to plant in, or for plants that require a soil type not found in the garden or when soil drainage in the garden is inferior. If growing more than one plant in a container, make sure that all have similar cultural requirements. Choose a container that is deep and large enough to allow root development and growth as well as proportional balance between the fully developed plant and the container. Plant large containers in the place you intend them to stay. All containers should have drainage holes. A mesh screen, broken clay pot pieces(crock) or a paper coffee filter placed over the hole will keep soil from washing out. The potting soil you select should be an appropriate mix for the plants you have chosen. Quality soils (or soil-less medias) absorb moisture readily and evenly when wet. If water runs off soil upon initial wetting, this is an indicator that your soil may not be as good as you think.
Prior to filling a container with soil, wet potting soil in the bag or place in a tub or wheelbarrow so that it is evenly moist. Fill container about halfway full or to a level that will allow plants, when planted, to be just below the rim of the pot. Rootballs should be level with soil line when project is complete. Water well.
ProblemsDiseases : Verticillium or Fusarium Wilt
Wilts may be contracted through infected seed, plant debris, or soil. This fungus begins and multiplies during the cool, moist season, becoming obvious when weather turns warm and dry. Plants wilt because the fungus damages their water conducting mechanisms. Overfertilization can worsen this problem. Able to overwinter in soil for many years, it is also carried and harbored in common weeds.
Prevention and Control: If possible, select resistant varieties. Keep nitrogen-heavy fertilizers to a minimum as well as over-irrigating as they encourage lush growth. Practice crop rotation and prune out or better yet remove infected plants.
Pest : Tomato Hornworm
These large green caterpillars have diagonal white stripes along their body with a prominent horn on their tail end. They are the larvae of the brown sphinx moth. Look for these caterpillars clinging to the undersides of leaves and stems. Even if you don't see them, you may know they were there because of the black excrement they left behind as well as the leaves they have chewed through. They are also fond of fruit.
Prevention and Control: Rotate tomato location each year and deeply till soil to expose pupae. Floating row covers in June or July help to prevent active moths from laying eggs. Handpick and destroy caterpillars when found. Consult your local garden center professional or county Cooperative Extension office for legal pesticide/chemical recommendations.
Diseases : Blossom End Rot
Blossom-end Rot is caused by several factors, all relating back to the plant's ability to utilize calcium in the soil. Calcium is only available to the plant when the soil is evenly moist. Another reason could be that there simply is not enough calcium in the soil. Other reasons are root damage, temperature swings or even a high salt content.
The problem usually appears as a soggy, sunken area on the end of the fruit early on. The area will darken over time and become more concave.
Prevention and Control: Plant resistant varieties and keep soil evenly moist, watering deeply, less frequently. Mulch will help to maintain the moisture level in the soil. Do not be tempted to over-fertilize or use uncomposted manure as both are high in salts. If all else fails, have your soil tested for a mineral imbalance.
Pest : Whiteflies
Whiteflies are small, winged insects that look like tiny moths, which attack many types of plants. The flying adult stage prefers the underside of leaves to feed and breed. Whiteflies can multiply quickly as a female can lay up to 500 eggs in a life span of 2 months. If a plant is infested with whiteflies, you will see a cloud of fleeing insects when the plant is disturbed. Whiteflies can weaken a plant, eventually leading to plant death if they are not checked. They can transmit many harmful plant viruses. They also produce a sweet substance called honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold.
Possible controls: keep weeds down; use screening in windows to keep them out; remove infested plants away from non-infested plants; use a reflective mulch (aluminum foil) under plants (this repels whiteflies); trap with yellow sticky cards, apply labeled pesticides; encourage natural enemies such as parasitic wasps in the garden; and sometimes a good steady shower of water will wash them off the plant.
Fungi : Powdery Mildew
Powdery Mildew is usually found on plants that do not have enough air circulation or adequate light. Problems are worse where nights are cool and days are warm and humid. The powdery white or gray fungus is usually found on the upper surface of leaves or fruit. Leaves will often turn yellow or brown, curl up, and drop off. New foliage emerges crinkled and distorted. Fruit will be dwarfed and often drops early.
Prevention and Control: Plant resistant varieties and space plants properly so they receive adequate light and air circulation. Always water from below, keeping water off the foliage. This is paramount for roses. Go easy on the nitrogen fertilizer. Apply fungicides according to label directions before problem becomes severe and follow directions exactly, not missing any required treatments. Sanitation is a must - clean up and remove all leaves, flowers, or debris in the fall and destroy.
Pest : Caterpillars
Caterpillars are the immature form of moths and butterflies. They are voracious feeders attacking a wide variety of plants. They can be highly destructive and are characterized as leaf feeders, stem borers, leaf rollers, cutworms and tent-formers.
Prevention and Control: keep weeds down, scout individual plants and remove caterpillars, apply labeled insecticides such as soaps and oils, take advantage of natural enemies such as parasitic wasps in the garden and use Bacillus thuringiensis (biological warfare) for some caterpillar species.
MiscellaneousGlossary : Annual
An annual is any plant that completes its life cycle in one growing season.
Glossary : Biennial
Biennial is a plant that takes two growing seasons to produce flowers and fruit. The first growing season, the plant stays in a rosette form, producing mainly foliage and roots. The second growing season the plant bolts, producing flowers and fruits or seeds.
Glossary : Viruses
Viruses, which are smaller than bacteria, are not living and do not replicate on their own. They must rely on the cellular mechanisms of their hosts to replicate. Because this greatly disrupts the cell's functionality, outward signs of a viral infection result in a plant disease with symptoms such as abnormal or stunted growth, damaged fruit, discolorations or spots.
Prevention and Control: Keep virus carriers such as aphids, leafhoppers, and thrips under control. These plant feeding insects spread viruses. Viruses can also be introduced by infected pollen or through plant openings (as when pruning). Begin by keeping the pathogen out of your garden. New plants should be checked, as well as tools and existing plants. Use only certified seed that is deemed disease-free. Plant only resistant varieties and create a discouraging environment by rotating crops, not planting closely related plants in the same area every year.